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張 旭

Pods - Kubernetes - 0 views

kubernetes.io/...pod

kubernetes pod system

shared by 張 旭 on 05 Jul 19 - No Cached
  • Pods are the smallest deployable units of computing
  • A Pod (as in a pod of whales or pea pod) is a group of one or more containersA lightweight and portable executable image that contains software and all of its dependencies. (such as Docker containers), with shared storage/network, and a specification for how to run the containers.
  • A Pod’s contents are always co-located and co-scheduled, and run in a shared context.
  • ...32 more annotations...
  • A Pod models an application-specific “logical host”
  • application containers which are relatively tightly coupled
  • being executed on the same physical or virtual machine would mean being executed on the same logical host.
  • The shared context of a Pod is a set of Linux namespaces, cgroups, and potentially other facets of isolation
  • Containers within a Pod share an IP address and port space, and can find each other via localhost
  • Containers in different Pods have distinct IP addresses and can not communicate by IPC without special configuration. These containers usually communicate with each other via Pod IP addresses.
  • Applications within a Pod also have access to shared volumesA directory containing data, accessible to the containers in a pod. , which are defined as part of a Pod and are made available to be mounted into each application’s filesystem.
  • a Pod is modelled as a group of Docker containers with shared namespaces and shared filesystem volumes
    • 張 旭
      張 旭 on 05 Jul 19
       
      類似 docker-compose 裡面宣告的同一坨？
  • Pods are considered to be relatively ephemeral (rather than durable) entities.
  • Pods are created, assigned a unique ID (UID), and scheduled to nodes where they remain until termination (according to restart policy) or deletion.
  • it can be replaced by an identical Pod
  • When something is said to have the same lifetime as a Pod, such as a volume, that means that it exists as long as that Pod (with that UID) exists.
  • uses a persistent volume for shared storage between the containers
  • Pods serve as unit of deployment, horizontal scaling, and replication
  • The applications in a Pod all use the same network namespace (same IP and port space), and can thus “find” each other and communicate using localhost
  • flat shared networking space
  • Containers within the Pod see the system hostname as being the same as the configured name for the Pod.
  • Volumes enable data to survive container restarts and to be shared among the applications within the Pod.
  • Individual Pods are not intended to run multiple instances of the same application
  • The individual containers may be versioned, rebuilt and redeployed independently.
  • Pods aren’t intended to be treated as durable entities.
  • Controllers like StatefulSet can also provide support to stateful Pods.
  • When a user requests deletion of a Pod, the system records the intended grace period before the Pod is allowed to be forcefully killed, and a TERM signal is sent to the main process in each container.
  • Once the grace period has expired, the KILL signal is sent to those processes, and the Pod is then deleted from the API server.
  • grace period
  • Pod is removed from endpoints list for service, and are no longer considered part of the set of running Pods for replication controllers.
  • When the grace period expires, any processes still running in the Pod are killed with SIGKILL.
  • By default, all deletes are graceful within 30 seconds.
  • You must specify an additional flag --force along with --grace-period=0 in order to perform force deletions.
  • Force deletion of a Pod is defined as deletion of a Pod from the cluster state and etcd immediately.
  • StatefulSet Pods
  • Processes within the container get almost the same privileges that are available to processes outside a container.
張 旭

Docker for AWS persistent data volumes | Docker Documentation - 0 views

docs.docker.com/...persistent-data-volumes

aws docker system

shared by 張 旭 on 08 Oct 18 - No Cached
  • Cloudstor is a modern volume plugin built by Docker
  • Docker swarm mode tasks and regular Docker containers can use a volume created with Cloudstor to mount a persistent data volume.
  • Global shared Cloudstor volumes mounted by all tasks in a swarm service.
  • ...14 more annotations...
  • Workloads running in a Docker service that require access to low latency/high IOPs persistent storage, such as a database engine, can use a relocatable Cloudstor volume backed by EBS.
  • Each relocatable Cloudstor volume is backed by a single EBS volume.
  • If a swarm task using a relocatable Cloudstor volume gets rescheduled to another node within the same availability zone as the original node where the task was running, Cloudstor detaches the backing EBS volume from the original node and attaches it to the new target node automatically.
  • in a different availability zone,
  • Cloudstor transfers the contents of the backing EBS volume to the destination availability zone using a snapshot, and cleans up the EBS volume in the original availability zone.
  • Typically the snapshot-based transfer process across availability zones takes between 2 and 5 minutes unless the work load is write-heavy.
  • A swarm task is not started until the volume it mounts becomes available
  • Sharing/mounting the same Cloudstor volume backed by EBS among multiple tasks is not a supported scenario and leads to data loss.
  • a Cloudstor volume to share data between tasks, choose the appropriate EFS backed shared volume option.
  • When multiple swarm service tasks need to share data in a persistent storage volume, you can use a shared Cloudstor volume backed by EFS.
  • a volume and its contents can be mounted by multiple swarm service tasks without the risk of data loss
  • over NFS
  • the persistent data backed by EFS volumes is always available.
  • shared Cloudstor volumes only work in those AWS regions where EFS is supported.
張 旭

Share Process Namespace between Containers in a Pod | Kubernetes - 0 views

kubernetes.io/...share-process-namespace

kubernetes pod namespace

shared by 張 旭 on 19 Aug 22 - No Cached
  • When process namespace sharing is enabled, processes in a container are visible to all other containers in the same pod.
  • It's even possible to access the file system of another container using the /proc/$pid/root link.
  • Pods share many resources so it makes sense they would also share a process namespace.
  • ...2 more annotations...
  • Processes are visible to other containers in the pod. This includes all information visible in /proc, such as passwords that were passed as arguments or environment variables. These are protected only by regular Unix permissions.
  • Container filesystems are visible to other containers in the pod through the /proc/$pid/root link. This makes debugging easier, but it also means that filesystem secrets are protected only by filesystem permissions.
  • 張 旭 on 19 Aug 22
     
    "When process namespace sharing is enabled, processes in a container are visible to all other containers in the same pod. "
張 旭

Volumes - Kubernetes - 0 views

kubernetes.io/...volumes

kubernetes volume disk nfs

shared by 張 旭 on 28 May 19 - No Cached
  • On-disk files in a Container are ephemeral,
  • when a Container crashes, kubelet will restart it, but the files will be lost - the Container starts with a clean state
  • In Docker, a volume is simply a directory on disk or in another Container.
  • ...105 more annotations...
  • A Kubernetes volume, on the other hand, has an explicit lifetime - the same as the Pod that encloses it.
  • a volume outlives any Containers that run within the Pod, and data is preserved across Container restarts.
    • 張 旭
      張 旭 on 06 Jul 19
       
      Kubernetes Volume 是跟著 Pod 的生命週期在走
  • Kubernetes supports many types of volumes, and a Pod can use any number of them simultaneously.
  • To use a volume, a Pod specifies what volumes to provide for the Pod (the .spec.volumes field) and where to mount those into Containers (the .spec.containers.volumeMounts field).
  • A process in a container sees a filesystem view composed from their Docker image and volumes.
  • Volumes can not mount onto other volumes or have hard links to other volumes.
  • Each Container in the Pod must independently specify where to mount each volume
  • localnfs
  • cephfs
  • awsElasticBlockStore
  • glusterfs
  • vsphereVolume
  • An awsElasticBlockStore volume mounts an Amazon Web Services (AWS) EBS Volume into your Pod.
  • the contents of an EBS volume are preserved and the volume is merely unmounted.
  • an EBS volume can be pre-populated with data, and that data can be “handed off” between Pods.
  • create an EBS volume using aws ec2 create-volume
  • the nodes on which Pods are running must be AWS EC2 instances
  • EBS only supports a single EC2 instance mounting a volume
  • check that the size and EBS volume type are suitable for your use!
  • A cephfs volume allows an existing CephFS volume to be mounted into your Pod.
  • the contents of a cephfs volume are preserved and the volume is merely unmounted.
    • 張 旭
      張 旭 on 06 Jul 19
       
      相當於自己的 AWS EBS
  • CephFS can be mounted by multiple writers simultaneously.
  • have your own Ceph server running with the share exported
  • configMap
  • The configMap resource provides a way to inject configuration data into Pods
  • When referencing a configMap object, you can simply provide its name in the volume to reference it
  • volumeMounts: - name: config-vol mountPath: /etc/config volumes: - name: config-vol configMap: name: log-config items: - key: log_level path: log_level
  • create a ConfigMap before you can use it.
  • A Container using a ConfigMap as a subPath volume mount will not receive ConfigMap updates.
  • An emptyDir volume is first created when a Pod is assigned to a Node, and exists as long as that Pod is running on that node.
  • When a Pod is removed from a node for any reason, the data in the emptyDir is deleted forever.
  • By default, emptyDir volumes are stored on whatever medium is backing the node - that might be disk or SSD or network storage, depending on your environment.
  • you can set the emptyDir.medium field to "Memory" to tell Kubernetes to mount a tmpfs (RAM-backed filesystem)
  • volumeMounts: - mountPath: /cache name: cache-volume volumes: - name: cache-volume emptyDir: {}
  • An fc volume allows an existing fibre channel volume to be mounted in a Pod.
  • configure FC SAN Zoning to allocate and mask those LUNs (volumes) to the target WWNs beforehand so that Kubernetes hosts can access them.
  • Flocker is an open-source clustered Container data volume manager. It provides management and orchestration of data volumes backed by a variety of storage backends.
  • emptyDir
  • flocker
  • A flocker volume allows a Flocker dataset to be mounted into a Pod
  • have your own Flocker installation running
  • A gcePersistentDisk volume mounts a Google Compute Engine (GCE) Persistent Disk into your Pod.
  • Using a PD on a Pod controlled by a ReplicationController will fail unless the PD is read-only or the replica count is 0 or 1
  • A glusterfs volume allows a Glusterfs (an open source networked filesystem) volume to be mounted into your Pod.
  • have your own GlusterFS installation running
  • A hostPath volume mounts a file or directory from the host node’s filesystem into your Pod.
  • a powerful escape hatch for some applications
  • access to Docker internals; use a hostPath of /var/lib/docker
  • allowing a Pod to specify whether a given hostPath should exist prior to the Pod running, whether it should be created, and what it should exist as
  • specify a type for a hostPath volume
  • the files or directories created on the underlying hosts are only writable by root.
  • hostPath: # directory location on host path: /data # this field is optional type: Directory
  • An iscsi volume allows an existing iSCSI (SCSI over IP) volume to be mounted into your Pod.
  • have your own iSCSI server running
  • A feature of iSCSI is that it can be mounted as read-only by multiple consumers simultaneously.
  • A local volume represents a mounted local storage device such as a disk, partition or directory.
  • Local volumes can only be used as a statically created PersistentVolume.
  • Compared to hostPath volumes, local volumes can be used in a durable and portable manner without manually scheduling Pods to nodes, as the system is aware of the volume’s node constraints by looking at the node affinity on the PersistentVolume.
  • If a node becomes unhealthy, then the local volume will also become inaccessible, and a Pod using it will not be able to run.
  • PersistentVolume spec using a local volume and nodeAffinity
  • PersistentVolume nodeAffinity is required when using local volumes. It enables the Kubernetes scheduler to correctly schedule Pods using local volumes to the correct node.
  • PersistentVolume volumeMode can now be set to “Block” (instead of the default value “Filesystem”) to expose the local volume as a raw block device.
  • When using local volumes, it is recommended to create a StorageClass with volumeBindingMode set to WaitForFirstConsumer
  • An nfs volume allows an existing NFS (Network File System) share to be mounted into your Pod.
  • NFS can be mounted by multiple writers simultaneously.
  • have your own NFS server running with the share exported
  • A persistentVolumeClaim volume is used to mount a PersistentVolume into a Pod.
  • PersistentVolumes are a way for users to “claim” durable storage (such as a GCE PersistentDisk or an iSCSI volume) without knowing the details of the particular cloud environment.
  • A projected volume maps several existing volume sources into the same directory.
  • All sources are required to be in the same namespace as the Pod. For more details, see the all-in-one volume design document.
  • Each projected volume source is listed in the spec under sources
  • A Container using a projected volume source as a subPath volume mount will not receive updates for those volume sources.
  • RBD volumes can only be mounted by a single consumer in read-write mode - no simultaneous writers allowed
  • A secret volume is used to pass sensitive information, such as passwords, to Pods
  • store secrets in the Kubernetes API and mount them as files for use by Pods
  • secret volumes are backed by tmpfs (a RAM-backed filesystem) so they are never written to non-volatile storage.
  • create a secret in the Kubernetes API before you can use it
  • A Container using a Secret as a subPath volume mount will not receive Secret updates.
  • StorageOS runs as a Container within your Kubernetes environment, making local or attached storage accessible from any node within the Kubernetes cluster.
  • Data can be replicated to protect against node failure. Thin provisioning and compression can improve utilization and reduce cost.
  • StorageOS provides block storage to Containers, accessible via a file system.
  • A vsphereVolume is used to mount a vSphere VMDK Volume into your Pod.
  • supports both VMFS and VSAN datastore.
  • create VMDK using one of the following methods before using with Pod.
  • share one volume for multiple uses in a single Pod.
  • The volumeMounts.subPath property can be used to specify a sub-path inside the referenced volume instead of its root.
  • volumeMounts: - name: workdir1 mountPath: /logs subPathExpr: $(POD_NAME)
  • env: - name: POD_NAME valueFrom: fieldRef: apiVersion: v1 fieldPath: metadata.name
  • Use the subPathExpr field to construct subPath directory names from Downward API environment variables
  • enable the VolumeSubpathEnvExpansion feature gate
  • The subPath and subPathExpr properties are mutually exclusive.
  • There is no limit on how much space an emptyDir or hostPath volume can consume, and no isolation between Containers or between Pods.
  • emptyDir and hostPath volumes will be able to request a certain amount of space using a resource specification, and to select the type of media to use, for clusters that have several media types.
  • the Container Storage Interface (CSI) and Flexvolume. They enable storage vendors to create custom storage plugins without adding them to the Kubernetes repository.
  • all volume plugins (like volume types listed above) were “in-tree” meaning they were built, linked, compiled, and shipped with the core Kubernetes binaries and extend the core Kubernetes API.
  • Container Storage Interface (CSI) defines a standard interface for container orchestration systems (like Kubernetes) to expose arbitrary storage systems to their container workloads.
  • Once a CSI compatible volume driver is deployed on a Kubernetes cluster, users may use the csi volume type to attach, mount, etc. the volumes exposed by the CSI driver.
  • The csi volume type does not support direct reference from Pod and may only be referenced in a Pod via a PersistentVolumeClaim object.
  • This feature requires CSIInlineVolume feature gate to be enabled:--feature-gates=CSIInlineVolume=true
  • In-tree plugins that support CSI Migration and have a corresponding CSI driver implemented are listed in the “Types of Volumes” section above.
  • Mount propagation allows for sharing volumes mounted by a Container to other Containers in the same Pod, or even to other Pods on the same node.
  • Mount propagation of a volume is controlled by mountPropagation field in Container.volumeMounts.
  • HostToContainer - This volume mount will receive all subsequent mounts that are mounted to this volume or any of its subdirectories.
  • Bidirectional - This volume mount behaves the same the HostToContainer mount. In addition, all volume mounts created by the Container will be propagated back to the host and to all Containers of all Pods that use the same volume.
  • Edit your Docker’s systemd service file. Set MountFlags as follows:MountFlags=shared
crazylion lee

How to record your terminal session on Linux - 0 views

www.howtoforge.com/...your-terminal-session-on-linux

session linux record terminal cwb

shared by crazylion lee on 15 Jun 16 - No Cached
  • crazylion lee on 15 Jun 16
     
    "Recording a terminal session may be important in helping someone learn a process, sharing information in an understandable way, and also presenting a series of commands in a proper manner. Whatever the purpose, there are many times when copy-pasting text from the terminal won't be very helpful while capturing a video of the process is quite far-fetched and may not be always possible. In this quick guide, we will take a look at the easiest way to record and share a terminal session in .gif format."
crazylion lee

Social Media Sharing Buttons. No JavaScript. No tracking. Super fast and easy. - 0 views

sharingbuttons.io

sharing social

shared by crazylion lee on 03 Aug 16 - No Cached
  • crazylion lee on 03 Aug 16
     
    "Super fast and easy Social Media Sharing Buttons. No JavaScript. No tracking."
張 旭

Helm | - 0 views

helm.sh/using_helm

kubernetes helm system

shared by 張 旭 on 17 Jul 19 - No Cached
  • Helm will figure out where to install Tiller by reading your Kubernetes configuration file (usually $HOME/.kube/config). This is the same file that kubectl uses.
  • kubectl cluster-info
  • Role-Based Access Control (RBAC) enabled
  • ...133 more annotations...
  • initialize the local CLI
  • install Tiller into your Kubernetes cluster
  • helm install
  • helm init --upgrade
  • By default, when Tiller is installed, it does not have authentication enabled.
  • helm repo update
  • Without a max history set the history is kept indefinitely, leaving a large number of records for helm and tiller to maintain.
  • helm init --upgrade
  • Whenever you install a chart, a new release is created.
  • one chart can be installed multiple times into the same cluster. And each can be independently managed and upgraded.
  • helm list function will show you a list of all deployed releases.
  • helm delete
  • helm status
  • you can audit a cluster’s history, and even undelete a release (with helm rollback).
  • the Helm server (Tiller).
  • The Helm client (helm)
  • brew install kubernetes-helm
  • Tiller, the server portion of Helm, typically runs inside of your Kubernetes cluster.
  • it can also be run locally, and configured to talk to a remote Kubernetes cluster.
  • Role-Based Access Control - RBAC for short
  • create a service account for Tiller with the right roles and permissions to access resources.
  • run Tiller in an RBAC-enabled Kubernetes cluster.
  • run kubectl get pods --namespace kube-system and see Tiller running.
  • helm inspect
  • Helm will look for Tiller in the kube-system namespace unless --tiller-namespace or TILLER_NAMESPACE is set.
  • For development, it is sometimes easier to work on Tiller locally, and configure it to connect to a remote Kubernetes cluster.
  • even when running locally, Tiller will store release configuration in ConfigMaps inside of Kubernetes.
  • helm version should show you both the client and server version.
  • Tiller stores its data in Kubernetes ConfigMaps, you can safely delete and re-install Tiller without worrying about losing any data.
  • helm reset
  • The --node-selectors flag allows us to specify the node labels required for scheduling the Tiller pod.
  • --override allows you to specify properties of Tiller’s deployment manifest.
  • helm init --override manipulates the specified properties of the final manifest (there is no “values” file).
  • The --output flag allows us skip the installation of Tiller’s deployment manifest and simply output the deployment manifest to stdout in either JSON or YAML format.
  • By default, tiller stores release information in ConfigMaps in the namespace where it is running.
  • switch from the default backend to the secrets backend, you’ll have to do the migration for this on your own.
  • a beta SQL storage backend that stores release information in an SQL database (only postgres has been tested so far).
  • Once you have the Helm Client and Tiller successfully installed, you can move on to using Helm to manage charts.
  • Helm requires that kubelet have access to a copy of the socat program to proxy connections to the Tiller API.
  • A Release is an instance of a chart running in a Kubernetes cluster. One chart can often be installed many times into the same cluster.
  • helm init --client-only
  • helm init --dry-run --debug
  • A panic in Tiller is almost always the result of a failure to negotiate with the Kubernetes API server
  • Tiller and Helm have to negotiate a common version to make sure that they can safely communicate without breaking API assumptions
  • helm delete --purge
  • Helm stores some files in $HELM_HOME, which is located by default in ~/.helm
  • A Chart is a Helm package. It contains all of the resource definitions necessary to run an application, tool, or service inside of a Kubernetes cluster.
  • it like the Kubernetes equivalent of a Homebrew formula, an Apt dpkg, or a Yum RPM file.
  • A Repository is the place where charts can be collected and shared.
  • Set the $HELM_HOME environment variable
  • each time it is installed, a new release is created.
  • Helm installs charts into Kubernetes, creating a new release for each installation. And to find new charts, you can search Helm chart repositories.
  • chart repository is named stable by default
  • helm search shows you all of the available charts
  • helm inspect
  • To install a new package, use the helm install command. At its simplest, it takes only one argument: The name of the chart.
  • If you want to use your own release name, simply use the --name flag on helm install
  • additional configuration steps you can or should take.
  • Helm does not wait until all of the resources are running before it exits. Many charts require Docker images that are over 600M in size, and may take a long time to install into the cluster.
  • helm status
  • helm inspect values
  • helm inspect values stable/mariadb
  • override any of these settings in a YAML formatted file, and then pass that file during installation.
  • helm install -f config.yaml stable/mariadb
  • --values (or -f): Specify a YAML file with overrides.
  • --set (and its variants --set-string and --set-file): Specify overrides on the command line.
  • Values that have been --set can be cleared by running helm upgrade with --reset-values specified.
  • Chart designers are encouraged to consider the --set usage when designing the format of a values.yaml file.
  • --set-file key=filepath is another variant of --set. It reads the file and use its content as a value.
  • inject a multi-line text into values without dealing with indentation in YAML.
  • An unpacked chart directory
  • When a new version of a chart is released, or when you want to change the configuration of your release, you can use the helm upgrade command.
  • Kubernetes charts can be large and complex, Helm tries to perform the least invasive upgrade.
  • It will only update things that have changed since the last release
  • $ helm upgrade -f panda.yaml happy-panda stable/mariadb
  • deployment
  • If both are used, --set values are merged into --values with higher precedence.
  • The helm get command is a useful tool for looking at a release in the cluster.
  • helm rollback
  • A release version is an incremental revision. Every time an install, upgrade, or rollback happens, the revision number is incremented by 1.
  • helm history
  • a release name cannot be re-used.
  • you can rollback a deleted resource, and have it re-activate.
  • helm repo list
  • helm repo add
  • helm repo update
  • The Chart Development Guide explains how to develop your own charts.
  • helm create
  • helm lint
  • helm package
  • Charts that are archived can be loaded into chart repositories.
  • chart repository server
  • Tiller can be installed into any namespace.
  • Limiting Tiller to only be able to install into specific namespaces and/or resource types is controlled by Kubernetes RBAC roles and rolebindings
  • Release names are unique PER TILLER INSTANCE
  • Charts should only contain resources that exist in a single namespace.
  • not recommended to have multiple Tillers configured to manage resources in the same namespace.
  • a client-side Helm plugin. A plugin is a tool that can be accessed through the helm CLI, but which is not part of the built-in Helm codebase.
  • Helm plugins are add-on tools that integrate seamlessly with Helm. They provide a way to extend the core feature set of Helm, but without requiring every new feature to be written in Go and added to the core tool.
  • Helm plugins live in $(helm home)/plugins
  • The Helm plugin model is partially modeled on Git’s plugin model
  • helm referred to as the porcelain layer, with plugins being the plumbing.
  • helm plugin install https://github.com/technosophos/helm-template
  • command is the command that this plugin will execute when it is called.
  • Environment variables are interpolated before the plugin is executed.
  • The command itself is not executed in a shell. So you can’t oneline a shell script.
  • Helm is able to fetch Charts using HTTP/S
  • Variables like KUBECONFIG are set for the plugin if they are set in the outer environment.
  • In Kubernetes, granting a role to an application-specific service account is a best practice to ensure that your application is operating in the scope that you have specified.
  • restrict Tiller’s capabilities to install resources to certain namespaces, or to grant a Helm client running access to a Tiller instance.
  • Service account with cluster-admin role
  • The cluster-admin role is created by default in a Kubernetes cluster
  • Deploy Tiller in a namespace, restricted to deploying resources only in that namespace
  • Deploy Tiller in a namespace, restricted to deploying resources in another namespace
  • When running a Helm client in a pod, in order for the Helm client to talk to a Tiller instance, it will need certain privileges to be granted.
  • SSL Between Helm and Tiller
  • The Tiller authentication model uses client-side SSL certificates.
  • creating an internal CA, and using both the cryptographic and identity functions of SSL.
  • Helm is a powerful and flexible package-management and operations tool for Kubernetes.
  • default installation applies no security configurations
  • with a cluster that is well-secured in a private network with no data-sharing or no other users or teams.
  • With great power comes great responsibility.
  • Choose the Best Practices you should apply to your helm installation
  • Role-based access control, or RBAC
  • Tiller’s gRPC endpoint and its usage by Helm
  • Kubernetes employ a role-based access control (or RBAC) system (as do modern operating systems) to help mitigate the damage that can be done if credentials are misused or bugs exist.
  • In the default installation the gRPC endpoint that Tiller offers is available inside the cluster (not external to the cluster) without authentication configuration applied.
  • Tiller stores its release information in ConfigMaps. We suggest changing the default to Secrets.
  • release information
  • charts
  • charts are a kind of package that not only installs containers you may or may not have validated yourself, but it may also install into more than one namespace.
  • As with all shared software, in a controlled or shared environment you must validate all software you install yourself before you install it.
  • Helm’s provenance tools to ensure the provenance and integrity of charts
  • 張 旭 on 17 Jul 19
     
    "Helm will figure out where to install Tiller by reading your Kubernetes configuration file (usually $HOME/.kube/config). This is the same file that kubectl uses."
crazylion lee

dbpatterns - create, share, explore database patterns - 0 views

dbpatterns.com

database patterns db Design

shared by crazylion lee on 08 Jun 16 - No Cached
  • crazylion lee on 08 Jun 16
     
    "Dbpatterns is a service that allows you to create, share, explore database models on the web."
crazylion lee

ShareX - Take screenshots or screencasts, annotate, upload and share URL in clipboard - 0 views

getsharex.com

screenshot screencapture windows

shared by crazylion lee on 08 Oct 15 - No Cached
  • crazylion lee on 08 Oct 15
     
    "Sharing has never been easier."
crazylion lee

transfer.sh - Easy and fast file sharing from the command-line. - 1 views

transfer.sh

file transfer web filesharing cli commandline

shared by crazylion lee on 29 Mar 16 - No Cached
  • crazylion lee on 29 Mar 16
     
    "Easy file sharing from the command line"
張 旭

Using Workflows to Schedule Jobs - CircleCI - 1 views

circleci.com/workflows

circleci CI deploy system

shared by 張 旭 on 25 Nov 18 - No Cached
  • A workflow is a set of rules for defining a collection of jobs and their run order.
  • Schedule workflows for jobs that should only run periodically.
  • run multiple jobs in parallel
  • ...37 more annotations...
  • rerun just the failed job
  • Builds without workflows require a build job.
  • Refer the YAML Anchors/Aliases documentation for information about how to alias and reuse syntax to keep your .circleci/config.yml file small.
  • workflow orchestration with two parallel jobs
  • jobs run according to configured requirements, each job waiting to start until the required job finishes successfully
  • requires: key
  • fans-out to run a set of acceptance test jobs in parallel, and finally fans-in to run a common deploy job.
  • Holding a Workflow for a Manual Approval
  • Workflows can be configured to wait for manual approval of a job before continuing to the next job
  • add a job to the jobs list with the key type: approval
  • approval is a special job type that is only available to jobs under the workflow key
  • The name of the job to hold is arbitrary - it could be wait or pause, for example, as long as the job has a type: approval key in it.
  • schedule a workflow to run at a certain time for specific branches.
  • The triggers key is only added under your workflows key
  • using cron syntax to represent Coordinated Universal Time (UTC) for specified branches.
  • By default, a workflow is triggered on every git push
  • the commit workflow has no triggers key and will run on every git push
  • The nightly workflow has a triggers key and will run on the specified schedule
  • Cron step syntax (for example, */1, */20) is not supported.
  • use a context to share environment variables
  • use the same shared environment variables when initiated by a user who is part of the organization.
  • CircleCI does not run workflows for tags unless you explicitly specify tag filters.
  • CircleCI branch and tag filters support the Java variant of regex pattern matching.
  • Each workflow has an associated workspace which can be used to transfer files to downstream jobs as the workflow progresses.
  • The workspace is an additive-only store of data.
  • Jobs can persist data to the workspace
  • Downstream jobs can attach the workspace to their container filesystem.
  • Attaching the workspace downloads and unpacks each layer based on the ordering of the upstream jobs in the workflow graph.
  • Workflows that include jobs running on multiple branches may require data to be shared using workspaces
  • To persist data from a job and make it available to other jobs, configure the job to use the persist_to_workspace key.
  • Files and directories named in the paths: property of persist_to_workspace will be uploaded to the workflow’s temporary workspace relative to the directory specified with the root key.
  • Configure a job to get saved data by configuring the attach_workspace key.
  • persist_to_workspace
  • attach_workspace
  • To rerun only a workflow’s failed jobs, click the Workflows icon in the app and select a workflow to see the status of each job, then click the Rerun button and select Rerun from failed.
  • if you do not see your workflows triggering, a configuration error is preventing the workflow from starting.
  • check your Workflows page of the CircleCI app (not the Job page)
  • 張 旭 on 25 Nov 18
     
    "A workflow is a set of rules for defining a collection of jobs and their run order."
張 旭

Glossary - CircleCI - 0 views

circleci.com/glossary

circleci CI system deploy

shared by 張 旭 on 25 Nov 18 - No Cached
  • User authentication may use LDAP for an instance of the CircleCI application that is installed on your private server or cloud
  • The first user to log into a private installation of CircleCI
  • Contexts provide a mechanism for securing and sharing environment variables across projects.
  • ...22 more annotations...
  • The environment variables are defined as name/value pairs and are injected at runtime.
  • The CircleCI Docker Layer Caching feature allows builds to reuse Docker image layers
  • from previous builds.
  • Image layers are stored in separate volumes in the cloud and are not shared between projects.
  • Layers may only be used by builds from the same project.
  • Environment variables store customer data that is used by a project.
  • Defines the underlying technology to run a job.
  • machine to run your job inside a full virtual machine.
  • docker to run your job inside a Docker container with a specified image
  • A job is a collection of steps.
  • The first image listed in config.yml
  • A CircleCI project shares the name of the code repository for which it automates workflows, tests, and deployment.
  • must be added with the Add Project button
  • Following a project enables a user to subscribe to email notifications for the project build status and adds the project to their CircleCI dashboard.
  • A step is a collection of executable commands
  • Users must be added to a GitHub or Bitbucket org to view or follow associated CircleCI projects.
  • Users may not view project data that is stored in environment variables.  
  • A Workflow is a set of rules for defining a collection of jobs and their run order.
  • Workflows are implemented as a directed acyclic graph (DAG) of jobs for greatest flexibility.
  • referred to as Pipelines
  • A workspace is a workflows-aware storage mechanism.
  • A workspace stores data unique to the job, which may be needed in downstream jobs.
張 旭

Persisting Data in Workflows: When to Use Caching, Artifacts, and Workspaces - CircleCI - 0 views

circleci.com/...ching-artifacts-and-workspaces

circleci deploy system CI volume share

shared by 張 旭 on 25 Nov 18 - No Cached
  • Repeatability is also important
  • When a CI process isn’t repeatable you’ll find yourself wasting time re-running jobs to get them to go green.
  • Workspaces persist data between jobs in a single Workflow.
  • ...9 more annotations...
  • Caching persists data between the same job in different Workflow builds.
  • Artifacts persist data after a Workflow has finished
  • When a Workspace is declared in a job, one or more files or directories can be added. Each addition creates a new layer in the Workspace filesystem. Downstreams jobs can then use this Workspace for its own needs or add more layers on top.
  • Unlike caching, Workspaces are not shared between runs as they no longer exists once a Workflow is complete.
  • Caching lets you reuse the data from expensive fetch operations from previous jobs.
  • A prime example is package dependency managers such as Yarn, Bundler, or Pip.
  • Caches are global within a project, a cache saved on one branch will be used by others so they should only be used for data that is OK to share across Branches
  • Artifacts are used for longer-term storage of the outputs of your build process.
  • If your project needs to be packaged in some form or fashion, say an Android app where the .apk file is uploaded to Google Play, that’s a great example of an artifact.
  • 張 旭 on 25 Nov 18
     
    "CircleCI 2.0 provides a number of different ways to move data into and out of jobs, persist data, and with the introduction of Workspaces, move data between jobs"
張 旭

Kubernetes Volumes Guide - Examples for NFS and Persistent Volume - 0 views

matthewpalmer.net/...ple-nfs-persistent-volume.html

kubernetes volume storage

shared by 張 旭 on 07 Jul 19 - No Cached
  • Persistent volumes exist beyond containers, pods, and nodes.
  • Volumes also let you share data between containers in the same pod.
  • data in that volume will be destroyed when the pod is restarted.
  • ...9 more annotations...
  • Persistent volumes are long-term storage in your Kubernetes cluster.
  • A pod uses a persistent volume claim to to get read and write access to the persistent volume.
  • NFS stands for Network File System – it's a shared filesystem that can be accessed over the network.
  • The NFS must already exist – Kubernetes doesn't run the NFS, pods in just access it.
  • what's already stored in the NFS is not deleted when a pod is destroyed. Data is persistent.
  • an NFS can be accessed from multiple pods at the same time. An NFS can be used to share data between pods!
  • volumes: - name: nfs-volume nfs: # URL for the NFS server server: 10.108.211.244 # Change this! path: /
  • volumeMounts: - name: nfs-volume mountPath: /var/nfs
  • Just add the volume to each pod, and add a volume mount to use the NFS volume from each container.
  • 張 旭 on 07 Jul 19
     
    "Persistent volumes exist beyond containers, pods, and nodes. "
張 旭

Helm | - 0 views

helm.sh/developing_charts

helm kubernetes chart development devops package

shared by 張 旭 on 05 Aug 19 - No Cached
  • A chart is a collection of files that describe a related set of Kubernetes resources.
  • A single chart might be used to deploy something simple, like a memcached pod, or something complex, like a full web app stack with HTTP servers, databases, caches, and so on.
  • Charts are created as files laid out in a particular directory tree, then they can be packaged into versioned archives to be deployed.
  • ...170 more annotations...
  • A chart is organized as a collection of files inside of a directory.
  • values.yaml # The default configuration values for this chart
  • charts/ # A directory containing any charts upon which this chart depends.
  • templates/ # A directory of templates that, when combined with values, # will generate valid Kubernetes manifest files.
  • version: A SemVer 2 version (required)
  • apiVersion: The chart API version, always "v1" (required)
  • Every chart must have a version number. A version must follow the SemVer 2 standard.
  • non-SemVer names are explicitly disallowed by the system.
  • When generating a package, the helm package command will use the version that it finds in the Chart.yaml as a token in the package name.
  • the appVersion field is not related to the version field. It is a way of specifying the version of the application.
  • appVersion: The version of the app that this contains (optional). This needn't be SemVer.
  • If the latest version of a chart in the repository is marked as deprecated, then the chart as a whole is considered to be deprecated.
  • deprecated: Whether this chart is deprecated (optional, boolean)
  • one chart may depend on any number of other charts.
  • dependencies can be dynamically linked through the requirements.yaml file or brought in to the charts/ directory and managed manually.
  • the preferred method of declaring dependencies is by using a requirements.yaml file inside of your chart.
  • A requirements.yaml file is a simple file for listing your dependencies.
  • The repository field is the full URL to the chart repository.
  • you must also use helm repo add to add that repo locally.
  • helm dependency update and it will use your dependency file to download all the specified charts into your charts/ directory for you.
  • When helm dependency update retrieves charts, it will store them as chart archives in the charts/ directory.
  • Managing charts with requirements.yaml is a good way to easily keep charts updated, and also share requirements information throughout a team.
  • All charts are loaded by default.
  • The condition field holds one or more YAML paths (delimited by commas). If this path exists in the top parent’s values and resolves to a boolean value, the chart will be enabled or disabled based on that boolean value.
  • The tags field is a YAML list of labels to associate with this chart.
  • all charts with tags can be enabled or disabled by specifying the tag and a boolean value.
  • The --set parameter can be used as usual to alter tag and condition values.
  • Conditions (when set in values) always override tags.
  • The first condition path that exists wins and subsequent ones for that chart are ignored.
  • The keys containing the values to be imported can be specified in the parent chart’s requirements.yaml file using a YAML list. Each item in the list is a key which is imported from the child chart’s exports field.
  • specifying the key data in our import list, Helm looks in the exports field of the child chart for data key and imports its contents.
  • the parent key data is not contained in the parent’s final values. If you need to specify the parent key, use the ‘child-parent’ format.
  • To access values that are not contained in the exports key of the child chart’s values, you will need to specify the source key of the values to be imported (child) and the destination path in the parent chart’s values (parent).
  • To drop a dependency into your charts/ directory, use the helm fetch command
  • A dependency can be either a chart archive (foo-1.2.3.tgz) or an unpacked chart directory.
  • name cannot start with _ or .. Such files are ignored by the chart loader.
  • a single release is created with all the objects for the chart and its dependencies.
  • Helm Chart templates are written in the Go template language, with the addition of 50 or so add-on template functions from the Sprig library and a few other specialized functions
  • When Helm renders the charts, it will pass every file in that directory through the template engine.
  • Chart developers may supply a file called values.yaml inside of a chart. This file can contain default values.
  • Chart users may supply a YAML file that contains values. This can be provided on the command line with helm install.
  • When a user supplies custom values, these values will override the values in the chart’s values.yaml file.
  • Template files follow the standard conventions for writing Go templates
  • {{default "minio" .Values.storage}}
  • Values that are supplied via a values.yaml file (or via the --set flag) are accessible from the .Values object in a template.
  • pre-defined, are available to every template, and cannot be overridden
  • the names are case sensitive
  • Release.Name: The name of the release (not the chart)
  • Release.IsUpgrade: This is set to true if the current operation is an upgrade or rollback.
  • Release.Revision: The revision number. It begins at 1, and increments with each helm upgrade
  • Chart: The contents of the Chart.yaml
  • Files: A map-like object containing all non-special files in the chart.
  • Files can be accessed using {{index .Files "file.name"}} or using the {{.Files.Get name}} or {{.Files.GetString name}} functions.
  • .helmignore
  • access the contents of the file as []byte using {{.Files.GetBytes}}
  • Any unknown Chart.yaml fields will be dropped
  • Chart.yaml cannot be used to pass arbitrarily structured data into the template.
  • A values file is formatted in YAML.
  • A chart may include a default values.yaml file
  • be merged into the default values file.
  • The default values file included inside of a chart must be named values.yaml
  • accessible inside of templates using the .Values object
  • Values files can declare values for the top-level chart, as well as for any of the charts that are included in that chart’s charts/ directory.
  • Charts at a higher level have access to all of the variables defined beneath.
  • lower level charts cannot access things in parent charts
  • Values are namespaced, but namespaces are pruned.
  • the scope of the values has been reduced and the namespace prefix removed
  • Helm supports special “global” value.
  • a way of sharing one top-level variable with all subcharts, which is useful for things like setting metadata properties like labels.
  • If a subchart declares a global variable, that global will be passed downward (to the subchart’s subcharts), but not upward to the parent chart.
  • global variables of parent charts take precedence over the global variables from subcharts.
  • helm lint
  • A chart repository is an HTTP server that houses one or more packaged charts
  • Any HTTP server that can serve YAML files and tar files and can answer GET requests can be used as a repository server.
  • Helm does not provide tools for uploading charts to remote repository servers.
  • the only way to add a chart to $HELM_HOME/starters is to manually copy it there.
  • Helm provides a hook mechanism to allow chart developers to intervene at certain points in a release’s life cycle.
  • Execute a Job to back up a database before installing a new chart, and then execute a second job after the upgrade in order to restore data.
  • Hooks are declared as an annotation in the metadata section of a manifest
  • Hooks work like regular templates, but they have special annotations
  • pre-install
  • post-install: Executes after all resources are loaded into Kubernetes
  • pre-delete
  • post-delete: Executes on a deletion request after all of the release’s resources have been deleted.
  • pre-upgrade
  • post-upgrade
  • pre-rollback
  • post-rollback: Executes on a rollback request after all resources have been modified.
  • crd-install
  • test-success: Executes when running helm test and expects the pod to return successfully (return code == 0).
  • test-failure: Executes when running helm test and expects the pod to fail (return code != 0).
  • Hooks allow you, the chart developer, an opportunity to perform operations at strategic points in a release lifecycle
  • Tiller then loads the hook with the lowest weight first (negative to positive)
  • Tiller returns the release name (and other data) to the client
  • If the resources is a Job kind, Tiller will wait until the job successfully runs to completion.
  • if the job fails, the release will fail. This is a blocking operation, so the Helm client will pause while the Job is run.
  • If they have hook weights (see below), they are executed in weighted order. Otherwise, ordering is not guaranteed.
  • good practice to add a hook weight, and set it to 0 if weight is not important.
  • The resources that a hook creates are not tracked or managed as part of the release.
  • leave the hook resource alone.
  • To destroy such resources, you need to either write code to perform this operation in a pre-delete or post-delete hook or add "helm.sh/hook-delete-policy" annotation to the hook template file.
  • Hooks are just Kubernetes manifest files with special annotations in the metadata section
  • One resource can implement multiple hooks
  • no limit to the number of different resources that may implement a given hook.
  • When subcharts declare hooks, those are also evaluated. There is no way for a top-level chart to disable the hooks declared by subcharts.
  • Hook weights can be positive or negative numbers but must be represented as strings.
  • sort those hooks in ascending order.
  • Hook deletion policies
  • "before-hook-creation" specifies Tiller should delete the previous hook before the new hook is launched.
  • By default Tiller will wait for 60 seconds for a deleted hook to no longer exist in the API server before timing out.
  • Custom Resource Definitions (CRDs) are a special kind in Kubernetes.
  • The crd-install hook is executed very early during an installation, before the rest of the manifests are verified.
  • A common reason why the hook resource might already exist is that it was not deleted following use on a previous install/upgrade.
  • Helm uses Go templates for templating your resource files.
  • two special template functions: include and required
  • include function allows you to bring in another template, and then pass the results to other template functions.
  • The required function allows you to declare a particular values entry as required for template rendering.
  • If the value is empty, the template rendering will fail with a user submitted error message.
  • When you are working with string data, you are always safer quoting the strings than leaving them as bare words
  • Quote Strings, Don’t Quote Integers
  • when working with integers do not quote the values
  • env variables values which are expected to be string
  • to include a template, and then perform an operation on that template’s output, Helm has a special include function
  • The above includes a template called toYaml, passes it $value, and then passes the output of that template to the nindent function.
  • Go provides a way for setting template options to control behavior when a map is indexed with a key that’s not present in the map
  • The required function gives developers the ability to declare a value entry as required for template rendering.
  • The tpl function allows developers to evaluate strings as templates inside a template.
  • Rendering a external configuration file
  • (.Files.Get "conf/app.conf")
  • Image pull secrets are essentially a combination of registry, username, and password.
  • Automatically Roll Deployments When ConfigMaps or Secrets change
  • configmaps or secrets are injected as configuration files in containers
  • a restart may be required should those be updated with a subsequent helm upgrade
  • The sha256sum function can be used to ensure a deployment’s annotation section is updated if another file changes
  • checksum/config: {{ include (print $.Template.BasePath "/configmap.yaml") . | sha256sum }}
  • helm upgrade --recreate-pods
  • "helm.sh/resource-policy": keep
  • resources that should not be deleted when Helm runs a helm delete
  • this resource becomes orphaned. Helm will no longer manage it in any way.
  • create some reusable parts in your chart
  • In the templates/ directory, any file that begins with an underscore(_) is not expected to output a Kubernetes manifest file.
  • by convention, helper templates and partials are placed in a _helpers.tpl file.
  • The current best practice for composing a complex application from discrete parts is to create a top-level umbrella chart that exposes the global configurations, and then use the charts/ subdirectory to embed each of the components.
  • SAP’s Converged charts: These charts install SAP Converged Cloud a full OpenStack IaaS on Kubernetes. All of the charts are collected together in one GitHub repository, except for a few submodules.
  • Deis’s Workflow: This chart exposes the entire Deis PaaS system with one chart. But it’s different from the SAP chart in that this umbrella chart is built from each component, and each component is tracked in a different Git repository.
  • YAML is a superset of JSON
  • any valid JSON structure ought to be valid in YAML.
  • As a best practice, templates should follow a YAML-like syntax unless the JSON syntax substantially reduces the risk of a formatting issue.
  • There are functions in Helm that allow you to generate random data, cryptographic keys, and so on.
  • a chart repository is a location where packaged charts can be stored and shared.
  • A chart repository is an HTTP server that houses an index.yaml file and optionally some packaged charts.
  • Because a chart repository can be any HTTP server that can serve YAML and tar files and can answer GET requests, you have a plethora of options when it comes down to hosting your own chart repository.
  • It is not required that a chart package be located on the same server as the index.yaml file.
  • A valid chart repository must have an index file. The index file contains information about each chart in the chart repository.
  • The Helm project provides an open-source Helm repository server called ChartMuseum that you can host yourself.
  • $ helm repo index fantastic-charts --url https://fantastic-charts.storage.googleapis.com
  • A repository will not be added if it does not contain a valid index.yaml
  • add the repository to their helm client via the helm repo add [NAME] [URL] command with any name they would like to use to reference the repository.
  • Helm has provenance tools which help chart users verify the integrity and origin of a package.
  • Integrity is established by comparing a chart to a provenance record
  • The provenance file contains a chart’s YAML file plus several pieces of verification information
  • Chart repositories serve as a centralized collection of Helm charts.
  • Chart repositories must make it possible to serve provenance files over HTTP via a specific request, and must make them available at the same URI path as the chart.
  • We don’t want to be “the certificate authority” for all chart signers. Instead, we strongly favor a decentralized model, which is part of the reason we chose OpenPGP as our foundational technology.
  • The Keybase platform provides a public centralized repository for trust information.
  • A chart contains a number of Kubernetes resources and components that work together.
  • A test in a helm chart lives under the templates/ directory and is a pod definition that specifies a container with a given command to run.
  • The pod definition must contain one of the helm test hook annotations: helm.sh/hook: test-success or helm.sh/hook: test-failure
  • helm test
  • nest your test suite under a tests/ directory like <chart-name>/templates/tests/
張 旭

Using Ansible and Ansible Tower with shared roles - 2 views

www.ansible.com/...nsible-tower-with-shared-roles

ansible devops architecture

shared by 張 旭 on 03 Oct 19 - No Cached
  • clearly defined roles for dedicated tasks
  • a predefined structure of folders and files to hold your automation code.
  • Roles can be part of your project repository.
  • ...8 more annotations...
  • a better way is to keep a role in its own repository.
  • to be available to a playbook, the role still needs to be included.
  • The best way to make shared roles available to your playbooks is to use a function built into Ansible itself: by using the command ansible-galaxy
  • ansible galaxy can read a file specifying which external roles need to be imported for a successful Ansible run: requirements.yml
  • requirements.yml ensures that the used role can be pinned to a certain release tag value, commit hash, or branch name.
  • Each time Ansible Tower checks out a project it looks for a roles/requirements.yml. If such a file is present, a new version of each listed role is copied to the local checkout of the project and thus available to the relevant playbooks.
  • stick to the directory name roles, sitting in the root of your project directory.
  • have one requirements.yml only, and keep it at roles/requirements.yml
  • 張 旭 on 03 Oct 19
     
    "clearly defined roles for dedicated tasks"
張 旭

Cluster Networking - Kubernetes - 0 views

kubernetes.io/...networking

kubernetes networking network system

shared by 張 旭 on 08 Jul 19 - No Cached
  • Networking is a central part of Kubernetes, but it can be challenging to understand exactly how it is expected to work
  • Highly-coupled container-to-container communications
  • Pod-to-Pod communications
  • ...57 more annotations...
  • this is the primary focus of this document
    • 張 旭
      張 旭 on 27 Aug 21
       
      Cluster Networking 所關注處理的是： Pod 到 Pod 之間的連線
  • Pod-to-Service communications
  • External-to-Service communications
  • Kubernetes is all about sharing machines between applications.
  • sharing machines requires ensuring that two applications do not try to use the same ports.
  • Dynamic port allocation brings a lot of complications to the system
  • Every Pod gets its own IP address
  • do not need to explicitly create links between Pods
  • almost never need to deal with mapping container ports to host ports.
  • Pods can be treated much like VMs or physical hosts from the perspectives of port allocation, naming, service discovery, load balancing, application configuration, and migration.
  • pods on a node can communicate with all pods on all nodes without NAT
  • agents on a node (e.g. system daemons, kubelet) can communicate with all pods on that node
  • pods in the host network of a node can communicate with all pods on all nodes without NAT
  • If your job previously ran in a VM, your VM had an IP and could talk to other VMs in your project. This is the same basic model.
  • containers within a Pod share their network namespaces - including their IP address
  • containers within a Pod can all reach each other’s ports on localhost
  • containers within a Pod must coordinate port usage
  • “IP-per-pod” model.
  • request ports on the Node itself which forward to your Pod (called host ports), but this is a very niche operation
  • The Pod itself is blind to the existence or non-existence of host ports.
  • AOS is an Intent-Based Networking system that creates and manages complex datacenter environments from a simple integrated platform.
  • Cisco Application Centric Infrastructure offers an integrated overlay and underlay SDN solution that supports containers, virtual machines, and bare metal servers.
  • AOS Reference Design currently supports Layer-3 connected hosts that eliminate legacy Layer-2 switching problems.
  • The AWS VPC CNI offers integrated AWS Virtual Private Cloud (VPC) networking for Kubernetes clusters.
  • users can apply existing AWS VPC networking and security best practices for building Kubernetes clusters.
  • Using this CNI plugin allows Kubernetes pods to have the same IP address inside the pod as they do on the VPC network.
  • The CNI allocates AWS Elastic Networking Interfaces (ENIs) to each Kubernetes node and using the secondary IP range from each ENI for pods on the node.
  • Big Cloud Fabric is a cloud native networking architecture, designed to run Kubernetes in private cloud/on-premises environments.
  • Cilium is L7/HTTP aware and can enforce network policies on L3-L7 using an identity based security model that is decoupled from network addressing.
  • CNI-Genie is a CNI plugin that enables Kubernetes to simultaneously have access to different implementations of the Kubernetes network model in runtime.
  • CNI-Genie also supports assigning multiple IP addresses to a pod, each from a different CNI plugin.
  • cni-ipvlan-vpc-k8s contains a set of CNI and IPAM plugins to provide a simple, host-local, low latency, high throughput, and compliant networking stack for Kubernetes within Amazon Virtual Private Cloud (VPC) environments by making use of Amazon Elastic Network Interfaces (ENI) and binding AWS-managed IPs into Pods using the Linux kernel’s IPvlan driver in L2 mode.
  • to be straightforward to configure and deploy within a VPC
  • Contiv provides configurable networking
  • Contrail, based on Tungsten Fabric, is a truly open, multi-cloud network virtualization and policy management platform.
  • DANM is a networking solution for telco workloads running in a Kubernetes cluster.
  • Flannel is a very simple overlay network that satisfies the Kubernetes requirements.
  • Any traffic bound for that subnet will be routed directly to the VM by the GCE network fabric.
  • sysctl net.ipv4.ip_forward=1
  • Jaguar provides overlay network using vxlan and Jaguar CNIPlugin provides one IP address per pod.
  • Knitter is a network solution which supports multiple networking in Kubernetes.
  • Kube-OVN is an OVN-based kubernetes network fabric for enterprises.
  • Kube-router provides a Linux LVS/IPVS-based service proxy, a Linux kernel forwarding-based pod-to-pod networking solution with no overlays, and iptables/ipset-based network policy enforcer.
  • If you have a “dumb” L2 network, such as a simple switch in a “bare-metal” environment, you should be able to do something similar to the above GCE setup.
  • Multus is a Multi CNI plugin to support the Multi Networking feature in Kubernetes using CRD based network objects in Kubernetes.
  • NSX-T can provide network virtualization for a multi-cloud and multi-hypervisor environment and is focused on emerging application frameworks and architectures that have heterogeneous endpoints and technology stacks.
  • NSX-T Container Plug-in (NCP) provides integration between NSX-T and container orchestrators such as Kubernetes
  • Nuage uses the open source Open vSwitch for the data plane along with a feature rich SDN Controller built on open standards.
  • OpenVSwitch is a somewhat more mature but also complicated way to build an overlay network
  • OVN is an opensource network virtualization solution developed by the Open vSwitch community.
  • Project Calico is an open source container networking provider and network policy engine.
  • Calico provides a highly scalable networking and network policy solution for connecting Kubernetes pods based on the same IP networking principles as the internet
  • Calico can be deployed without encapsulation or overlays to provide high-performance, high-scale data center networking.
  • Calico can also be run in policy enforcement mode in conjunction with other networking solutions such as Flannel, aka canal, or native GCE, AWS or Azure networking.
  • Romana is an open source network and security automation solution that lets you deploy Kubernetes without an overlay network
  • Weave Net runs as a CNI plug-in or stand-alone. In either version, it doesn’t require any configuration or extra code to run, and in both cases, the network provides one IP address per pod - as is standard for Kubernetes.
  • The network model is implemented by the container runtime on each node.
張 旭

architecture - Difference between a "coroutine" and a "thread"? - Stack Overflow - 0 views

stackoverflow.com/...tween-a-coroutine-and-a-thread

programming

shared by 張 旭 on 09 Jun 22 - No Cached
  • Co stands for cooperation. A co routine is asked to (or better expected to) willingly suspend its execution to give other co-routines a chance to execute too. So a co-routine is about sharing CPU resources (willingly) so others can use the same resource as oneself is using.
  • A thread on the other hand does not need to suspend its execution. Being suspended is completely transparent to the thread and the thread is forced by underlying hardware to suspend itself.
  • co-routines can not be concurrently executed and race conditions can not occur.
  • ...8 more annotations...
  • Concurrency is the separation of tasks to provide interleaved execution.
  • Parallelism is the simultaneous execution of multiple pieces of work in order to increase speed.
  • With threads, the operating system switches running threads preemptively according to its scheduler, which is an algorithm in the operating system kernel.
  • With coroutines, the programmer and programming language determine when to switch coroutines
  • In contrast to threads, which are pre-emptively scheduled by the operating system, coroutine switches are cooperative, meaning the programmer (and possibly the programming language and its runtime) controls when a switch will happen.
  • preemption
  • Coroutines are a form of sequential processing: only one is executing at any given time
  • Threads are (at least conceptually) a form of concurrent processing: multiple threads may be executing at any given time.
  • 張 旭 on 09 Jun 22
     
    "Co stands for cooperation. A co routine is asked to (or better expected to) willingly suspend its execution to give other co-routines a chance to execute too. So a co-routine is about sharing CPU resources (willingly) so others can use the same resource as oneself is using."
crazylion lee

Home - Automated interactive transcription tool - Trint ∙ Transforming Talk - 0 views

trint.com

automated interactive transcription tool 自動 翻譯

shared by crazylion lee on 25 Aug 16 - No Cached
  • crazylion lee on 25 Aug 16
     
    "The toolkit that lets you transcribe, search, edit and share media content online."
crazylion lee

I don't understand Python's Asyncio | Armin Ronacher's Thoughts and Writings - 0 views

lucumr.pocoo.org/...i-dont-understand-asyncio

python io async

shared by crazylion lee on 27 Nov 16 - No Cached
  • crazylion lee on 27 Nov 16
     
    "Recently I started looking into Python's new asyncio module a bit more. The reason for this is that I needed to do something that works better with evented IO and I figured I might give the new hot thing in the Python world a try. Primarily what I learned from this exercise is that I it's a much more complex system than I expected and I am now at the point where I am very confident that I do not know how to use it properly. It's not conceptionally hard to understand and borrows a lot from Twisted, but it has so many elements that play into it that I'm not sure any more how the individual bits and pieces are supposed to go together. Since I'm not clever enough to actually propose anything better I just figured I share my thoughts about what confuses me instead so that others might be able to use that in some capacity to understand it."
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