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張 旭

Ask HN: What are the best practises for using SSH keys? | Hacker News - 0 views

  • Make sure you use full disk encryption and never stand up from your machine without locking it, and make sure you keep your local machine patched.
  • I'm more focused on just stealing your keys from you regardless of length
  • attacks that aren't after your keys specifically, e.g. your home directory gets stolen.
  • ...19 more annotations...
  • ED25519 is more vulnerable to quantum computation than is RSA
  • best practice to be using a hardware token
  • to use a yubikey via gpg: with this method you use your gpg subkey as an ssh key
  • sit down and spend an hour thinking about your backup and recovery strategy first
  • never share a private keys between physical devices
  • allows you to revoke a single credential if you lose (control over) that device
  • If a private key ever turns up on the wrong machine, you *know* the key and both source and destination machines have been compromised.
  • centralized management of authentication/authorization
  • I have setup a VPS, disabled passwords, and setup a key with a passphrase to gain access. At this point my greatest worry is losing this private key, as that means I can't access the server.What is a reasonable way to backup my private key?
  • a mountable disk image that's encrypted
  • a system that can update/rotate your keys across all of your servers on the fly in case one is compromised or assumed to be compromised.
  • different keys for different purposes per client device
  • fall back to password plus OTP
  • relying completely on the security of your disk, against either physical or cyber.
  • It is better to use a different passphrase for each key but it is also less convenient unless you're using a password manager (personally, I'm using KeePass)
  • - RSA is pretty standard, and generally speaking is fairly secure for key lengths >=2048. RSA-2048 is the default for ssh-keygen, and is compatible with just about everything.
  • public-key authentication has somewhat unexpected side effect of preventing MITM per this security consulting firm
  • Disable passwords and only allow keys even for root with PermitRootLogin without-password
  • You should definitely use a different passphrase for keys stored on separate computers,
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    "Make sure you use full disk encryption and never stand up from your machine without locking it, and make sure you keep your local machine patched"
張 旭

Kubernetes Components | Kubernetes - 0 views

  • A Kubernetes cluster consists of a set of worker machines, called nodes, that run containerized applications
  • Every cluster has at least one worker node.
  • The control plane manages the worker nodes and the Pods in the cluster.
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  • The control plane's components make global decisions about the cluster
  • Control plane components can be run on any machine in the cluster.
  • for simplicity, set up scripts typically start all control plane components on the same machine, and do not run user containers on this machine
  • The API server is the front end for the Kubernetes control plane.
  • kube-apiserver is designed to scale horizontally—that is, it scales by deploying more instances. You can run several instances of kube-apiserver and balance traffic between those instances.
  • Kubernetes cluster uses etcd as its backing store, make sure you have a back up plan for those data.
  • watches for newly created Pods with no assigned node, and selects a node for them to run on.
  • Factors taken into account for scheduling decisions include: individual and collective resource requirements, hardware/software/policy constraints, affinity and anti-affinity specifications, data locality, inter-workload interference, and deadlines.
  • each controller is a separate process, but to reduce complexity, they are all compiled into a single binary and run in a single process.
  • Node controller
  • Job controller
  • Endpoints controller
  • Service Account & Token controllers
  • The cloud controller manager lets you link your cluster into your cloud provider's API, and separates out the components that interact with that cloud platform from components that only interact with your cluster.
  • If you are running Kubernetes on your own premises, or in a learning environment inside your own PC, the cluster does not have a cloud controller manager.
  • An agent that runs on each node in the cluster. It makes sure that containers are running in a Pod.
  • The kubelet takes a set of PodSpecs that are provided through various mechanisms and ensures that the containers described in those PodSpecs are running and healthy.
  • The kubelet doesn't manage containers which were not created by Kubernetes.
  • kube-proxy is a network proxy that runs on each node in your cluster, implementing part of the Kubernetes Service concept.
  • kube-proxy maintains network rules on nodes. These network rules allow network communication to your Pods from network sessions inside or outside of your cluster.
  • kube-proxy uses the operating system packet filtering layer if there is one and it's available.
  • Kubernetes supports several container runtimes: Docker, containerd, CRI-O, and any implementation of the Kubernetes CRI (Container Runtime Interface).
  • Addons use Kubernetes resources (DaemonSet, Deployment, etc) to implement cluster features
  • namespaced resources for addons belong within the kube-system namespace.
  • all Kubernetes clusters should have cluster DNS,
  • Cluster DNS is a DNS server, in addition to the other DNS server(s) in your environment, which serves DNS records for Kubernetes services.
  • Containers started by Kubernetes automatically include this DNS server in their DNS searches.
  • Container Resource Monitoring records generic time-series metrics about containers in a central database, and provides a UI for browsing that data.
  • A cluster-level logging mechanism is responsible for saving container logs to a central log store with search/browsing interface.
crazylion lee

ZuzooVn/machine-learning-for-software-engineers: A complete daily plan for studying to ... - 0 views

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    "A complete daily plan for studying to become a machine learning engineer."
張 旭

Introduction - Packer by HashiCorp - 0 views

  • A machine image is a single static unit that contains a pre-configured operating system and installed software which is used to quickly create new running machines.
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    "A machine image is a single static unit that contains a pre-configured operating system and installed software which is used to quickly create new running machines."
crazylion lee

Machine Learning for Everyday Tasks - 0 views

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    "Machine learning is often thought to be too complicated for everyday development tasks. We often associate it with things like big data, data mining, data science, and artificial intelligence. Sometimes it feels something like this:"
crazylion lee

Approaching (Almost) Any Machine Learning Problem | Abhishek Thakur | No Free Hunch - 0 views

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    "Approaching (Almost) Any Machine Learning Problem | Abhishek Thakur"
張 旭

VMware ISO - Builders - Packer by HashiCorp - 0 views

  • Packer can use a remote VMware Hypervisor to build the virtual machine.
  • enable GuestIPHack
  • When using a remote VMware Hypervisor, the builder still downloads the ISO and various files locally, and uploads these to the remote machine.
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  • Packer needs to decide on a port to use for VNC when building remotely.
  • vnc_disable_password - This must be set to "true" when using VNC with ESXi 6.5 or 6.7
  • remote_type (string) - The type of remote machine that will be used to build this VM rather than a local desktop product. The only value accepted for this currently is esx5. If this is not set, a desktop product will be used. By default, this is not set.
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    "Packer can use a remote VMware Hypervisor to build the virtual machine."
張 旭

Production environment | Kubernetes - 0 views

  • to promote an existing cluster for production use
  • Separating the control plane from the worker nodes.
  • Having enough worker nodes available
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  • You can use role-based access control (RBAC) and other security mechanisms to make sure that users and workloads can get access to the resources they need, while keeping workloads, and the cluster itself, secure. You can set limits on the resources that users and workloads can access by managing policies and container resources.
  • you need to plan how to scale to relieve increased pressure from more requests to the control plane and worker nodes or scale down to reduce unused resources.
  • Managed control plane: Let the provider manage the scale and availability of the cluster's control plane, as well as handle patches and upgrades.
  • The simplest Kubernetes cluster has the entire control plane and worker node services running on the same machine.
  • You can deploy a control plane using tools such as kubeadm, kops, and kubespray.
  • Secure communications between control plane services are implemented using certificates.
  • Certificates are automatically generated during deployment or you can generate them using your own certificate authority.
  • Separate and backup etcd service: The etcd services can either run on the same machines as other control plane services or run on separate machines
  • Create multiple control plane systems: For high availability, the control plane should not be limited to a single machine
  • Some deployment tools set up Raft consensus algorithm to do leader election of Kubernetes services. If the primary goes away, another service elects itself and take over.
  • Groups of zones are referred to as regions.
  • if you installed with kubeadm, there are instructions to help you with Certificate Management and Upgrading kubeadm clusters.
  • Production-quality workloads need to be resilient and anything they rely on needs to be resilient (such as CoreDNS).
  • Add nodes to the cluster: If you are managing your own cluster you can add nodes by setting up your own machines and either adding them manually or having them register themselves to the cluster’s apiserver.
  • Set up node health checks: For important workloads, you want to make sure that the nodes and pods running on those nodes are healthy.
  • Authentication: The apiserver can authenticate users using client certificates, bearer tokens, an authenticating proxy, or HTTP basic auth.
  • Authorization: When you set out to authorize your regular users, you will probably choose between RBAC and ABAC authorization.
  • Role-based access control (RBAC): Lets you assign access to your cluster by allowing specific sets of permissions to authenticated users. Permissions can be assigned for a specific namespace (Role) or across the entire cluster (ClusterRole).
  • Attribute-based access control (ABAC): Lets you create policies based on resource attributes in the cluster and will allow or deny access based on those attributes.
  • Set limits on workload resources
  • Set namespace limits: Set per-namespace quotas on things like memory and CPU
  • Prepare for DNS demand: If you expect workloads to massively scale up, your DNS service must be ready to scale up as well.
crazylion lee

https://states-language.net/spec.html#example - 0 views

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    "This document describes a JSON-based language used to describe state machines declaratively. The state machines thus defined may be executed by software. In this document, the software is referred to as "the interpreter"."
crazylion lee

Machine Learning Crash Course: Part 1 · ML@B - 0 views

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    "Machine Learning Crash Course"
crazylion lee

GitHub - eriklindernoren/ML-From-Scratch: Bare bones Python implementations of various ... - 0 views

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    "Bare bones Python implementations of various Machine Learning models and algorithms."
張 旭

Flynn: first preview release | Hacker News - 0 views

  • Etcd and Zookeeper provide essentially the same functionality. They are both a strongly consistent key/value stores that support notifications to clients of changes. These two projects are limited to service discovery
  • So lets say you had a client application that would talk to a node application that could be on any number of servers. What you could do is hard code that list into your application and randomly select one, in order to "fake" load balancing. However every time a machine went up or down you would have to update that list.
  • What Consul provides is you just tell your app to connect to "mynodeapp.consul" and then consul will give you the proper address of one of your node apps.
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  • Consul and Skydock are both applications that build on top of a tool like Zookeeper and Etcd.
  • What a developer ideally wants to do is just push code and not have to worry about what servers are running what, and worry about failover and the like
  • What Flynn provides (if I get it), is a diy Heroku like platform
  • Another project that I believe may be similar to Flynn is Apache Mesos.
  • a self hosted Heroku
  • Google Omega is Google's answer to Apache Mesos
  • Omega would need a service like Raft to understand what services are currently available
  • Raft is a consensus algorithm for keeping a set of distributed state machines in a consistent state.
  • I want to use Docker, but it has no easy way to say "take this file that contains instructions and make everything". You can write Dockerfiles, but you can only use one part of the stack in them, otherwise you run into trouble.
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    " So lets say you had a client application that would talk to a node application that could be on any number of servers. What you could do is hard code that list into your application and randomly select one, in order to "fake" load balancing. However every time a machine went up or down you would have to update that list. What Consul provides is you just tell your app to connect to "mynodeapp.consul" and then consul will give you the proper address of one of your node apps."
張 旭

Choosing an Executor Type - CircleCI - 0 views

  • Containers are an instance of the Docker Image you specify and the first image listed in your configuration is the primary container image in which all steps run.
  • In this example, all steps run in the container created by the first image listed under the build job
  • If you experience increases in your run times due to installing additional tools during execution, it is best practice to use the Building Custom Docker Images Documentation to create a custom image with tools that are pre-loaded in the container to meet the job requirements.
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  • The machine option runs your jobs in a dedicated, ephemeral VM
  • Using the machine executor gives your application full access to OS resources and provides you with full control over the job environment.
  • Using machine may require additional fees in a future pricing update.
  • Using the macos executor allows you to run your job in a macOS environment on a VM.
  • In a multi-image configuration job, all steps are executed in the container created by the first image listed.
  • All containers run in a common network and every exposed port will be available on localhost from a primary container.
  • If you want to work with private images/registries, please refer to Using Private Images.
  • Docker also has built-in image caching and enables you to build, run, and publish Docker images via Remote Docker.
  • if you require low-level access to the network or need to mount external volumes consider using machine
crazylion lee

Distill is dedicated to making machine learning clear and dynamic - 0 views

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    "Machine Learning Research Should Be Clear, Dynamic and Vivid. Distill Is Here to Help."
crazylion lee

saiprashanths/dl-setup: Instructions for setting up the software on your deep learning ... - 0 views

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    "Instructions for setting up the software on your deep learning machine"
crazylion lee

MAME Multiple Arcade Machine Emulator - 0 views

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    "MAME originally stood for Multiple Arcade Machine Emulator. MAME's purpose is to preserve decades of software history. As electronic technology continues to rush forward, MAME prevents this important "vintage" software from being lost and forgotten. This is achieved by documenting the hardware and how it functions. The source code to MAME serves as this documentation. The fact that the software is usable serves primarily to validate the accuracy of the documentation (how else can you prove that you have recreated the hardware faithfully?). Over time, MAME absorbed the sister-project MESS (Multi Emulator Super System), so MAME now documents a wide variety of (mostly vintage) computers, video game consoles and calculators, in addition to the arcade video games that were its initial focus."
張 旭

How to Use Docker on OS X: The Missing Guide | Viget - 0 views

  • Docker is a client-server application.
  • The Docker server is a daemon that does all the heavy lifting: building and downloading images, starting and stopping containers, and the like. It exposes a REST API for remote management.
  • The Docker client is a command line program that communicates with the Docker server using the REST API.
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  • interact with Docker by using the client to send commands to the server.
  • The machine running the Docker server is called the Docker host
  • Docker uses features only available to Linux, that machine must be running Linux (more specifically, the Linux kernel).
  • boot2docker is a “lightweight Linux distribution made specifically to run Docker containers.”
  • Docker server will run inside our boot2docker VM
  • boot2docker, not OS X, is the Docker host, not OS X.
  • Docker mounts volumes from the boot2docker VM, not from OS X
  • initialize boot2docker (we only have to do this once):
  • The Docker client assumes the Docker host is the current machine. We need to tell it to use our boot2docker VM by setting the DOCKER_HOST environment variable
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