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張 旭

Swarm mode key concepts | Docker Documentation - 0 views

docs.docker.com/...key-concepts

docker cluster system server HA

shared by 張 旭 on 16 Jun 17 - No Cached
  • The cluster management and orchestration features embedded in the Docker Engine are built using SwarmKit.
  • Docker engines participating in a cluster are running in swarm mode
  • A swarm is a cluster of Docker engines, or nodes, where you deploy services
  • ...19 more annotations...
  • When you run Docker without using swarm mode, you execute container commands.
  • When you run the Docker in swarm mode, you orchestrate services.
  • You can run swarm services and standalone containers on the same Docker instances.
  • A node is an instance of the Docker engine participating in the swarm
  • You can run one or more nodes on a single physical computer or cloud server
  • To deploy your application to a swarm, you submit a service definition to a manager node.
  • Manager nodes also perform the orchestration and cluster management functions required to maintain the desired state of the swarm.
  • Manager nodes elect a single leader to conduct orchestration tasks.
  • Worker nodes receive and execute tasks dispatched from manager nodes.
  • service is the definition of the tasks to execute on the worker nodes
  • When you create a service, you specify which container image to use and which commands to execute inside running containers.
  • replicated services model, the swarm manager distributes a specific number of replica tasks among the nodes based upon the scale you set in the desired state.
  • global services, the swarm runs one task for the service on every available node in the cluster.
  • A task carries a Docker container and the commands to run inside the container
  • Manager nodes assign tasks to worker nodes according to the number of replicas set in the service scale.
  • Once a task is assigned to a node, it cannot move to another node
  • If you do not specify a port, the swarm manager assigns the service a port in the 30000-32767 range.
  • External components, such as cloud load balancers, can access the service on the PublishedPort of any node in the cluster whether or not the node is currently running the task for the service.
  • Swarm mode has an internal DNS component that automatically assigns each service in the swarm a DNS entry.
張 旭

Manage swarm security with public key infrastructure (PKI) | Docker Documentation - 0 views

docs.docker.com/...pki

docker swarm cluster system security

shared by 張 旭 on 07 Sep 18 - No Cached
  • The nodes in a swarm use mutual Transport Layer Security (TLS) to authenticate, authorize, and encrypt the communications with other nodes in the swarm.
  • By default, the manager node generates a new root Certificate Authority (CA) along with a key pair, which are used to secure communications with other nodes that join the swarm.
  • The manager node also generates two tokens to use when you join additional nodes to the swarm: one worker token and one manager token.
  • ...3 more annotations...
  • Each time a new node joins the swarm, the manager issues a certificate to the node
  • By default, each node in the swarm renews its certificate every three months.
  • a cluster CA key or a manager node is compromised, you can rotate the swarm root CA so that none of the nodes trust certificates signed by the old root CA anymore.
  • 張 旭 on 07 Sep 18
     
    "The nodes in a swarm use mutual Transport Layer Security (TLS) to authenticate, authorize, and encrypt the communications with other nodes in the swarm."
張 旭

Deploy services to a swarm | Docker Documentation - 0 views

docs.docker.com/...services

docker swarm system

shared by 張 旭 on 07 Sep 18 - No Cached
  • Swarm services use a declarative model, which means that you define the desired state of the service, and rely upon Docker to maintain this state.
  • To create a single-replica service with no extra configuration, you only need to supply the image name.
  • A service can be in a pending state if its image is unavailable
  • ...12 more annotations...
  • If your image is available on a private registry which requires login, use the --with-registry-auth flag
  • When you update a service, Docker stops its containers and restarts them with the new configuration.
  • When updating an existing service, the flag is --publish-add. There is also a --publish-rm flag to remove a port that was previously published.
  • To update the command an existing service runs, you can use the --args flag.
  • force the service to use a specific version of the image
  • If the manager can’t resolve the tag to a digest, each worker node is responsible for resolving the tag to a digest, and different nodes may use different versions of the image.
  • After you create a service, its image is never updated unless you explicitly run docker service update with the --image flag as described below.
  • When you run service update with the --image flag, the swarm manager queries Docker Hub or your private Docker registry for the digest the tag currently points to and updates the service tasks to use that digest.
  • You can publish a service task’s port directly on the swarm node where that service is running.
  • You can rely on the routing mesh. When you publish a service port, the swarm makes the service accessible at the target port on every node, regardless of whether there is a task for the service running on that node or not.
  • To publish a service’s ports externally to the swarm, use the --publish <PUBLISHED-PORT>:<SERVICE-PORT> flag.
  • published port on every swarm node
張 旭

How services work | Docker Documentation - 0 views

docs.docker.com/...services

docker swarm cluster system

shared by 張 旭 on 07 Sep 18 - No Cached
  • a service is the image for a microservice within the context of some larger application.
  • When you create a service, you specify which container image to use and which commands to execute inside running containers.
  • an overlay network for the service to connect to other services in the swarm
  • ...13 more annotations...
  • In the swarm mode model, each task invokes exactly one container
  • A task is analogous to a “slot” where the scheduler places a container.
  • A task is the atomic unit of scheduling within a swarm.
  • A task is a one-directional mechanism. It progresses monotonically through a series of states: assigned, prepared, running, etc.
  • Docker swarm mode is a general purpose scheduler and orchestrator.
  • Hypothetically, you could implement other types of tasks such as virtual machine tasks or non-containerized process tasks.
  • If all nodes are paused or drained, and you create a service, it is pending until a node becomes available.
  • reserve a specific amount of memory for a service.
  • impose placement constraints on the service
  • As the administrator of a swarm, you declare the desired state of your swarm, and the manager works with the nodes in the swarm to create that state.
  • two types of service deployments, replicated and global.
  • A global service is a service that runs one task on every node.
  • Good candidates for global services are monitoring agents, an anti-virus scanners or other types of containers that you want to run on every node in the swarm.
張 旭

Use swarm mode routing mesh | Docker Documentation - 0 views

docs.docker.com/...ingress

docker swarm cluster system server HA networking

shared by 張 旭 on 16 Jun 17 - No Cached
  • Docker Engine swarm mode makes it easy to publish ports for services to make them available to resources outside the swarm.
  • All nodes participate in an ingress routing mesh.
  • routing mesh enables each node in the swarm to accept connections on published ports for any service running in the swarm, even if there’s no task running on the node.
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  • Port 7946 TCP/UDP for container network discovery
  • Port 4789 UDP for the container ingress network.
  • When you access port 8080 on any node, the swarm load balancer routes your request to an active container.
  • The routing mesh listens on the published port for any IP address assigned to the node.
  • publish a port for an existing service
  • To use an external load balancer without the routing mesh, set --endpoint-mode to dnsrr instead of the default value of vip
張 旭

Manage nodes in a swarm | Docker Documentation - 0 views

docs.docker.com/...manage-nodes

docker swarm system

shared by 張 旭 on 07 Sep 18 - No Cached
  • Drain means the scheduler doesn’t assign new tasks to the node. The scheduler shuts down any existing tasks and schedules them on an available node.
  • Reachable means the node is a manager node participating in the Raft consensus quorum. If the leader node becomes unavailable, the node is eligible for election as the new leader.
  • If a manager node becomes unavailable, you should either join a new manager node to the swarm or promote a worker node to be a manager.
  • ...8 more annotations...
  • docker node inspect self --pretty
  • docker node update --availability drain node
  • use node labels in service constraints
  • The labels you set for nodes using docker node update apply only to the node entity within the swarm
  • node labels can be used to limit critical tasks to nodes that meet certain requirements
  • promote a worker node to the manager role
  • demote a manager node to the worker role
  • If the last manager node leaves the swarm, the swarm becomes unavailable requiring you to take disaster recovery measures.
張 旭

What's the Docker Swarm "-advertise-addr"? - Blog | BoxBoat - 0 views

boxboat.com/...ts-docker-swarm-advertise-addr

docker swarm networking

shared by 張 旭 on 11 Sep 18 - No Cached
  • To put it simply, the --advertise-addr is the address other nodes in the Docker swarm use to connect into your node.
  • a port number which defaults to 2377
  • The --listen-addr is the address that the swarm service listens on for incoming connections.
  • ...2 more annotations...
  • The default for --listen-addr is to listen on all interfaces on TCP port 2377 (0.0.0.0:2377)
  • Depending on your network architecture, you may want your swarm management interface only accessible on a management network that could be separate from a data and/or public network that are each attached to a physical server.
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.
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  • 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

Swarm task states | Docker Documentation - 0 views

docs.docker.com/...swarm-task-states

docker swarm system

shared by 張 旭 on 07 Sep 18 - No Cached
  • Each service can start multiple tasks.
  • Tasks are execution units that run once to completion.
  • The task progresses forward through a number of states, and its state doesn’t go backward.
張 旭

Swarm Mode Cluster - Træfik - 0 views

docs.traefik.io/...swarm-mode

docker proxy system

shared by 張 旭 on 06 Sep 18 - No Cached
  • The only requirement for Træfik to work with swarm mode is that it needs to run on a manager node
  • 張 旭 on 06 Sep 18
     
    "The only requirement for Træfik to work with swarm mode is that it needs to run on a manager node"
張 旭

Deploy a registry server | Docker Documentation - 0 views

docs.docker.com/...deploying

docker system

shared by 張 旭 on 06 Sep 18 - No Cached
  • By default, secrets are mounted into a service at /run/secrets/<secret-name>
  • docker secret create
  • If you use a distributed storage driver, such as Amazon S3, you can use a fully replicated service. Each worker can write to the storage back-end without causing write conflicts.
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  • You can access the service on port 443 of any swarm node. Docker sends the requests to the node which is running the service.
  • --publish published=443,target=443
  • The most important aspect is that a load balanced cluster of registries must share the same resources
  • S3 or Azure, they should be accessing the same resource and share an identical configuration.
  • you must make sure you are properly sending the X-Forwarded-Proto, X-Forwarded-For, and Host headers to their “client-side” values. Failure to do so usually makes the registry issue redirects to internal hostnames or downgrading from https to http.
  • A properly secured registry should return 401 when the “/v2/” endpoint is hit without credentials
  • registries should always implement access restrictions.
  • REGISTRY_AUTH=htpasswd
  • REGISTRY_AUTH_HTPASSWD_PATH=/auth/htpasswd
  • The registry also supports delegated authentication which redirects users to a specific trusted token server. This approach is more complicated to set up, and only makes sense if you need to fully configure ACLs and need more control over the registry’s integration into your global authorization and authentication systems.
  • 張 旭 on 06 Sep 18
     
    "You can access the service on port 443 of any swarm node. Docker sends the requests to the node which is running the service. "
張 旭

Networking with overlay networks | Docker Documentation - 0 views

docs.docker.com/...network-tutorial-overlay

docker networking

shared by 張 旭 on 14 Sep 18 - No Cached
  • The manager host will function as both a manager and a worker, which means it can both run service tasks and manage the swarm.
  • connected together using an overlay network called ingress
  • each of them now has an overlay network called ingress and a bridge network called docker_gwbridge
  • ...7 more annotations...
  • The docker_gwbridge connects the ingress network to the Docker host’s network interface so that traffic can flow to and from swarm managers and workers
  • recommended that you use separate overlay networks for each application or group of applications which will work together
  • You don’t need to create the overlay network on the other nodes, beacause it will be automatically created when one of those nodes starts running a service task which requires it.
  • The default publish mode of ingress, which is used when you do not specify a mode for the --publish flag, means that if you browse to port 80 on manager, worker-1, or worker-2, you will be connected to port 80 on one of the 5 service tasks, even if no tasks are currently running on the node you browse to.
  • Even though overlay networks are automatically created on swarm worker nodes as needed, they are not automatically removed.
  • The -dit flags mean to start the container detached (in the background), interactive (with the ability to type into it), and with a TTY (so you can see the input and output).
  • alpine containers running ash, which is Alpine’s default shell rather than bash
crazylion lee

Locust - A modern load testing framework - 1 views

locust.io

testing performance python loadtest load test http

shared by crazylion lee on 21 Nov 16 - No Cached
  • crazylion lee on 21 Nov 16
     
    "Define user behaviour with Python code, and swarm your system with millions of simultaneous users. "
張 旭

LXC vs Docker: Why Docker is Better | UpGuard - 0 views

www.upguard.com/...docker-vs-lxc

docker container devops

shared by 張 旭 on 28 Jun 21 - No Cached
  • LXC (LinuX Containers) is a OS-level virtualization technology that allows creation and running of multiple isolated Linux virtual environments (VE) on a single control host.
  • Docker, previously called dotCloud, was started as a side project and only open-sourced in 2013. It is really an extension of LXC’s capabilities.
  • run processes in isolation.
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  • Docker is developed in the Go language and utilizes LXC, cgroups, and the Linux kernel itself. Since it’s based on LXC, a Docker container does not include a separate operating system; instead it relies on the operating system’s own functionality as provided by the underlying infrastructure.
  • Docker acts as a portable container engine, packaging the application and all its dependencies in a virtual container that can run on any Linux server.
  • a VE there is no preloaded emulation manager software as in a VM.
  • In a VE, the application (or OS) is spawned in a container and runs with no added overhead, except for a usually minuscule VE initialization process.
  • LXC will boast bare metal performance characteristics because it only packages the needed applications.
  • the OS is also just another application that can be packaged too.
  • a VM, which packages the entire OS and machine setup, including hard drive, virtual processors and network interfaces. The resulting bloated mass usually takes a long time to boot and consumes a lot of CPU and RAM.
  • don’t offer some other neat features of VM’s such as IaaS setups and live migration.
  • LXC as supercharged chroot on Linux. It allows you to not only isolate applications, but even the entire OS.
  • Libvirt, which allows the use of containers through the LXC driver by connecting to 'lxc:///'.
  • 'LXC', is not compatible with libvirt, but is more flexible with more userspace tools.
  • Portable deployment across machines
  • Versioning: Docker includes git-like capabilities for tracking successive versions of a container
  • Component reuse: Docker allows building or stacking of already created packages.
  • Shared libraries: There is already a public registry (http://index.docker.io/ ) where thousands have already uploaded the useful containers they have created.
  • Docker taking the devops world by storm since its launch back in 2013.
  • LXC, while older, has not been as popular with developers as Docker has proven to be
  • LXC having a focus on sys admins that’s similar to what solutions like the Solaris operating system, with its Solaris Zones, Linux OpenVZ, and FreeBSD, with its BSD Jails virtualization system
  • it started out being built on top of LXC, Docker later moved beyond LXC containers to its own execution environment called libcontainer.
  • Unlike LXC, which launches an operating system init for each container, Docker provides one OS environment, supplied by the Docker Engine
  • LXC tooling sticks close to what system administrators running bare metal servers are used to
  • The LXC command line provides essential commands that cover routine management tasks, including the creation, launch, and deletion of LXC containers.
  • Docker containers aim to be even lighter weight in order to support the fast, highly scalable, deployment of applications with microservice architecture.
  • With backing from Canonical, LXC and LXD have an ecosystem tightly bound to the rest of the open source Linux community.
  • Docker Swarm
  • Docker Trusted Registry
  • Docker Compose
  • Docker Machine
  • Kubernetes facilitates the deployment of containers in your data center by representing a cluster of servers as a single system.
  • Swarm is Docker’s clustering, scheduling and orchestration tool for managing a cluster of Docker hosts. 
  • rkt is a security minded container engine that uses KVM for VM-based isolation and packs other enhanced security features. 
  • Apache Mesos can run different kinds of distributed jobs, including containers. 
  • Elastic Container Service is Amazon’s service for running and orchestrating containerized applications on AWS
  • LXC offers the advantages of a VE on Linux, mainly the ability to isolate your own private workloads from one another. It is a cheaper and faster solution to implement than a VM, but doing so requires a bit of extra learning and expertise.
  • Docker is a significant improvement of LXC’s capabilities.
張 旭

What is DevOps? | Atlassian - 0 views

www.atlassian.com/devops

devops system

shared by 張 旭 on 13 Nov 18 - No Cached
  • DevOps is a set of practices that automates the processes between software development and IT teams, in order that they can build, test, and release software faster and more reliably.
  • increased trust, faster software releases, ability to solve critical issues quickly, and better manage unplanned work.
  • bringing together the best of software development and IT operations.
  • ...39 more annotations...
  • DevOps is a culture, a movement, a philosophy.
  • a firm handshake between development and operations
  • DevOps isn’t magic, and transformations don’t happen overnight.
  • Infrastructure as code
  • Culture is the #1 success factor in DevOps.
  • Building a culture of shared responsibility, transparency and faster feedback is the foundation of every high performing DevOps team.
  •  'not our problem' mentality
  • DevOps is that change in mindset of looking at the development process holistically and breaking down the barrier between Dev and Ops.
  • Speed is everything.
  • Lack of automated test and review cycles block the release to production and poor incident response time kills velocity and team confidence
  • Open communication helps Dev and Ops teams swarm on issues, fix incidents, and unblock the release pipeline faster.
  • Unplanned work is a reality that every team faces–a reality that most often impacts team productivity.
  • “cross-functional collaboration.”
  • All the tooling and automation in the world are useless if they aren’t accompanied by a genuine desire on the part of development and IT/Ops professionals to work together.
  • DevOps doesn’t solve tooling problems. It solves human problems.
  • Forming project- or product-oriented teams to replace function-based teams is a step in the right direction.
  • sharing a common goal and having a plan to reach it together
  • join sprint planning sessions, daily stand-ups, and sprint demos.
  • DevOps culture across every department
  • open channels of communication, and talk regularly
  • DevOps isn’t one team’s job. It’s everyone’s job.
  • automation eliminates repetitive manual work, yields repeatable processes, and creates reliable systems.
  • Build, test, deploy, and provisioning automation
  • continuous delivery: the practice of running each code change through a gauntlet of automated tests, often facilitated by cloud-based infrastructure, then packaging up successful builds and promoting them up toward production using automated deploys.
  • automated deploys alert IT/Ops to server “drift” between environments, which reduces or eliminates surprises when it’s time to release.
  • “configuration as code.”
  • when DevOps uses automated deploys to send thoroughly tested code to identically provisioned environments, “Works on my machine!” becomes irrelevant.
  • A DevOps mindset sees opportunities for continuous improvement everywhere.
  • regular retrospectives
  • A/B testing
  • failure is inevitable. So you might as well set up your team to absorb it, recover, and learn from it (some call this “being anti-fragile”).
  • Postmortems focus on where processes fell down and how to strengthen them – not on which team member f'ed up the code.
  • Our engineers are responsible for QA, writing, and running their own tests to get the software out to customers.
  • How long did it take to go from development to deployment? 
  • How long does it take to recover after a system failure?
  • service level agreements (SLAs)
  • Devops isn't any single person's job. It's everyone's job.
  • DevOps is big on the idea that the same people who build an application should be involved in shipping and running it.
  • developers and operators pair with each other in each phase of the application’s lifecycle.
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