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Tags: command-line tools kubernetes k8s k9s
Clipped on: 2019-10-25

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Kubernetes CLI To Manage Your Clusters In Style!
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Image (Asset 3/16) alt= .github/ISSUE_TEMPLATE updates 7 months ago .semaphore init drop 9 months ago assets add release notes 8 days ago change_logs update docs 8 days ago cmd Update description 3 days ago internal Merge pull request #384 from paivagustavo/invalidate-cache-when-chang… 5 hours ago skins reworked skins 4 months ago .dockerignore bug fixes + maintenance items 4 months ago .gitignore Add vim undo files to .gitignore last month .goreleaser.yml added confirm dialog for Michael's rollout restart feature 8 days ago .travis.yml rev up go to 1.13 last month CNAME cleanup + tests check 9 months ago Dockerfile bug fixes + maintenance items 4 months ago LICENSE Updated docs 8 months ago Makefile added columns for jobs 7 months ago README.md Merge branch 'master' of github.com-derailed:derailed/k9s 2 days ago go.mod cleaning up deps 24 days ago go.sum cleaning up deps 24 days ago main.go clean and bugs fixes 5 months ago

README.md

Image (Asset 4/16) alt=K9s - Kubernetes CLI To Manage Your Clusters In Style!

K9s provides a curses based terminal UI to interact with your Kubernetes clusters. The aim of this project is to make it easier to navigate, observe and manage your applications in the wild. K9s continually watches Kubernetes for changes and offers subsequent commands to interact with observed Kubernetes resources.


Image (Asset 5/16) alt=Installation

K9s is available on Linux, OSX and Windows platforms.

  • Binaries for Linux, Windows and Mac are available as tarballs in the release page.

  • Via Homebrew or LinuxBrew for OSX and Linux

    brew install derailed/k9s/k9s
  • Building from source K9s was built using go 1.13 or above. In order to build K9 from source you must:

    1. Clone the repo

    2. Add the following command in your go.mod file

      replace (
        github.com/derailed/k9s => MY_K9S_CLONED_GIT_REPO
      )
      
    3. Build and run the executable

      go run main.go

PreFlight Checks

  • K9s uses 256 colors terminal mode. On `Nix system make sure TERM is set accordingly.

    export TERM=xterm-256color

Screenshots

  1. Pods Image (Asset 6/16) alt=Demo Video

    The Command Line

    # List all available CLI options
    k9s help
    # To get info about K9s runtime (logs, configs, etc..)
    k9s info
    # To run K9s in a given namespace
    k9s -n mycoolns
    # Start K9s in an existing KubeConfig context
    k9s --context coolCtx

    Key Bindings

    K9s uses aliases to navigate most K8s resources.

    Command Result Example
    :alias<ENTER> View a Kubernetes resource aliases :po<ENTER>
    ? Show keyboard shortcuts and help
    Ctrl-a Show all available resource alias select+<ENTER> to view
    /filterENTER Filter out a resource view given a filter /bumblebeetuna
    /-l label-selectorENTER Filter resource view by labels /-l app=fred
    <Esc> Bails out of command/filter mode
    d,v, e, l,... Key mapping to describe, view, edit, view logs,... d (describes a resource)
    :ctx<ENTER> To view and switch to another Kubernetes context :+ctx+<ENTER>
    Ctrl-d To delete a resource (TAB and ENTER to confirm)
    Ctrl-k To delete a resource (no confirmation dialog)
    :q, Ctrl-c To bail out of K9s

    K9s config file ($HOME/.k9s/config.yml)

    K9s keeps its configurations in a dot file in your home directory.

    NOTE: This is still in flux and will change while in pre-release stage!

    k9s:
      # Indicates api-server poll intervals.
      refreshRate: 2
      # Indicates log view maximum buffer size. Default 1k lines.
      logBufferSize: 200
      # Indicates how many lines of logs to retrieve from the api-server. Default 200 lines.
      logRequestSize: 200
      # Indicates the current kube context. Defaults to current context
      currentContext: minikube
      # Indicates the current kube cluster. Defaults to current context cluster
      currentCluster: minikube
      # Persists per cluster preferences for favorite namespaces and view.
      clusters:
        cooln:
          namespace:
            active: coolio
            favorites:
            - cassandra
            - default
          view:
            active: po
        minikube:
          namespace:
            active: all
            favorites:
            - all
            - kube-system
            - default
          view:
            active: dp

    Aliases

    In K9s you can define your own command aliases (shortnames) to access your resources. In your $HOME/.k9s define a file called alias.yml. A K9s alias defines pairs of alias:gvr. A gvr represents a fully qualified Kubernetes resource identifier. Here is an example of an alias file:

    # $HOME/.k9s/alias.yml
    alias:
      pp: v1/pods
      crb: rbac.authorization.k8s.io/v1/clusterrolebindings

    Using this alias file, you can now type pp/crb to list pods, clusterrolebindings respectively.


    Plugins

    K9s allows you to define your own cluster commands via plugins. K9s will look at $HOME/.k9s/plugin.yml to locate available plugins. A plugin is defined as follows:

    # $HOME/.k9s/plugin.yml
    plugin:
      fred:
        shortCut: Ctrl-L
        description: "Pod logs"
        scopes:
        - po
        command: /usr/local/bin/kubectl
        background: false
        args:
        - logs
        - -f
        - $NAME
        - -n
        - $NAMESPACE
        - --context
        - $CONTEXT

    This defines a plugin for viewing logs on a selected pod using CtrlL mnemonic.

    The shortcut option represents the command a user would type to activate the plugin. The command represents adhoc commands the plugin runs upon activation. The scopes defines a collection of views shortnames for which the plugin shortcut will be made available to the user.

    K9s does provide additional environment variables for you to customize your plugins. Currently, the available environment variables are as follows:

    • $NAMESPACE -- the selected resource namespace
    • $NAME -- the selected resource name
    • $KUBECONFIG -- the KubeConfig location.
    • $CLUSTER the active cluster name
    • $CONTEXT the active context name
    • $USER the active user
    • $GROUPS the active groups
    • $COLX the column at index X for the viewed resource

    NOTE: This is an experimental feature! Options and layout may change in future K9s releases as this feature solidifies.


    Benchmarking

    K9s integrates Hey from the brilliant and super talented Jaana Dogan of Google fame. Hey is a CLI tool to benchmark HTTP endpoints similar to AB bench. This preliminary feature currently supports benchmarking port-forwards and services (Read the paint on this is way fresh!).

    To setup a port-forward, you will need to navigate to the PodView, select a pod and a container that exposes a given port. Using SHIFT-F a dialog comes up to allow you to specify a local port to forward. Once acknowledged, you can navigate to the PortForward view (alias pf) listing out your active port-forwards. Selecting a port-forward and using CTRL-B will run a benchmark on that HTTP endpoint. To view the results of your benchmark runs, go to the Benchmarks view (alias be). You should now be able to select a benchmark and view the run stats details by pressing <ENTER>. NOTE: Port-forwards only last for the duration of the K9s session and will be terminated upon exit.

    Initially, the benchmarks will run with the following defaults:

    • Concurrency Level: 1
    • Number of Requests: 200
    • HTTP Verb: GET
    • Path: /

    The PortForward view is backed by a new K9s config file namely: $HOME/.k9s/bench-mycluster.yml. Each cluster you connect to will have its own bench config file. Changes to this file should automatically update the PortForward view to indicate how you want to run your benchmarks.

    Here is a sample benchmarks.yml configuration. Please keep in mind this file will likely change in subsequent releases!

    # This file resides in $HOME/.k9s/bench-mycluster.yml
    benchmarks:
      # Indicates the default concurrency and number of requests setting if a container or service rule does not match.
      defaults:
        # One concurrent connection
        concurrency: 1
        # 500 requests will be sent to an endpoint
        requests: 500
      containers:
        # Containers section allows you to configure your http container's endpoints and benchmarking settings.
        # NOTE: the container ID syntax uses namespace/pod_name:container_name
        default/nginx:nginx:
          # Benchmark a container named nginx using POST HTTP verb using http://localhost:port/bozo URL and headers.
          concurrency: 1
          requests: 10000
          http:
            path: /bozo
            method: POST
            body:
              {"fred":"blee"}
            header:
              Accept:
                - text/html
              Content-Type:
                - application/json
      services:
        # Similary you can Benchmark an HTTP service exposed either via nodeport, loadbalancer types.
        # Service ID is ns/svc-name
        default/nginx:
          # Hit the service with 5 concurrent sessions
          concurrency: 5
          # Issues a total of 500 requests
          requests: 500
          http:
            method: GET
            # This setting will depend on whether service is nodeport or loadbalancer. Nodeport may require vendor port tuneling setting.
            # Set this to a node if nodeport or LB if applicable. IP or dns name.
            host: 10.11.13.14
            path: /bumblebeetuna
          auth:
            user: jean-baptiste-emmanuel
            password: Zorg!

    K9s RBAC FU

    On RBAC enabled clusters, you would need to give your users/groups capabilities so that they can use K9s to explore their Kubernetes cluster. K9s needs minimally read privileges at both the cluster and namespace level to display resources and metrics.

    These rules below are just suggestions. You will need to customize them based on your environment policies. If you need to edit/delete resources extra Fu will be necessary.

    NOTE! Cluster/Namespace access may change in the future as K9s evolves.

    NOTE! We expect K9s to keep running even in atrophied clusters/namespaces. Please file issues if this is not the case!

    Cluster RBAC scope

    ---
    # K9s Reader ClusterRole
    kind: ClusterRole
    apiVersion: rbac.authorization.k8s.io/v1
    metadata:
      name: k9s
    rules:
      # Grants RO access to cluster resources node and namespace
      - apiGroups: [""]
        resources: ["nodes", "namespaces"]
        verbs: ["get", "list", "watch"]
      # Grants RO access to RBAC resources
      - apiGroups: ["rbac.authorization.k8s.io"]
        resources: ["clusterroles", "roles", "clusterrolebindings", "rolebindings"]
        verbs: ["get", "list", "watch"]
      # Grants RO access to CRD resources
      - apiGroups: ["apiextensions.k8s.io"]
        resources: ["customresourcedefinitions"]
        verbs: ["get", "list", "watch"]
      # Grants RO access to metric server
      - apiGroups: ["metrics.k8s.io"]
        resources: ["nodes", "pods"]
        verbs: ["get", "list", "watch"]
    
    ---
    # Sample K9s user ClusterRoleBinding
    apiVersion: rbac.authorization.k8s.io/v1
    kind: ClusterRoleBinding
    metadata:
      name: k9s
    subjects:
      - kind: User
        name: fernand
        apiGroup: rbac.authorization.k8s.io
    roleRef:
      kind: ClusterRole
      name: k9s
      apiGroup: rbac.authorization.k8s.io

    Namespace RBAC scope

    If your users are constrained to certain namespaces, K9s will need to following role to enable read access to namespaced resources.

    ---
    # K9s Reader Role (default namespace)
    kind: Role
    apiVersion: rbac.authorization.k8s.io/v1
    metadata:
      name: k9s
      namespace: default
    rules:
      # Grants RO access to most namespaced resources
      - apiGroups: ["", "apps", "autoscaling", "batch", "extensions"]
        resources: ["*"]
        verbs: ["get", "list", "watch"]
      # Grants RO access to metric server
      - apiGroups: ["metrics.k8s.io"]
        resources: ["pods"]
        verbs:
          - get
          - list
          - watch
    
    ---
    # Sample K9s user RoleBinding
    apiVersion: rbac.authorization.k8s.io/v1
    kind: RoleBinding
    metadata:
      name: k9s
      namespace: default
    subjects:
      - kind: User
        name: fernand
        apiGroup: rbac.authorization.k8s.io
    roleRef:
      kind: Role
      name: k9s
      apiGroup: rbac.authorization.k8s.io

    Skins

    You can style K9s based on your own sense of style and look. This is very much an experimental feature at this time, more will be added/modified if this feature has legs so thread accordingly!

    By default a K9s view displays resource information using the following coloring scheme:

    1. Blue - All good.
    2. Orange/Red - Represents a potential issue with the resource ie a pod is not in a running state.
    3. Green - Indicates a row has changed. A change delta indicator indicates which column changed.

    Skins are YAML files, that enable a user to change K9s presentation layer. K9s skins are loaded from $HOME/.k9s/skin.yml. If a skin file is detected then the skin would be loaded if not the current stock skin remains in effect.

    Below is a sample skin file, more skins would be available in the skins directory, just simply copy any of these in your user's home dir as skin.yml.

    # InTheNavy Skin...
    k9s:
      # General K9s styles
      body:
        fgColor: dodgerblue
        bgColor: white
        logoColor: blue
      # ClusterInfoView styles.
      info:
        fgColor: lightskyblue
        sectionColor: steelblue
      frame:
        # Borders styles.
        border:
          fgColor: dodgerblue
          focusColor: aliceblue
        # MenuView attributes and styles.
        menu:
          fgColor: darkblue
          keyColor: cornflowerblue
          # Used for favorite namespaces
          numKeyColor: cadetblue
        # CrumbView attributes for history navigation.
        crumbs:
          fgColor: white
          bgColor: steelblue
          activeColor: skyblue
        # Resource status and update styles
        status:
          newColor: blue
          modifyColor: powderblue
          addColor: lightskyblue
          errorColor: indianred
          highlightcolor: royalblue
          killColor: slategray
          completedColor: gray
        # Border title styles.
        title:
          fgColor: aqua
          bgColor: white
          highlightColor: skyblue
          counterColor: slateblue
          filterColor: slategray
      # TableView attributes.
      table:
        fgColor: blue
        bgColor: darkblue
        cursorColor: aqua
        # Header row styles.
        header:
          fgColor: white
          bgColor: darkblue
          sorterColor: orange
      views:
        # YAML info styles.
        yaml:
          keyColor: steelblue
          colonColor: blue
          valueColor: royalblue
        # Logs styles.
        logs:
          fgColor: white
          bgColor: black

    Available color names are defined below:

    Color Names
    black maroon green olive navy
    purple teal silver gray red
    lime yellow blue fuchsia aqua
    white aliceblue antiquewhite aquamarine azure
    beige bisque blanchedalmond blueviolet brown
    burlywood cadetblue chartreuse chocolate coral
    cornflowerblue cornsilk crimson darkblue darkcyan
    darkgoldenrod darkgray darkgreen darkkhaki darkmagenta
    darkolivegreen darkorange darkorchid darkred darksalmon
    darkseagreen darkslateblue darkslategray darkturquoise darkviolet
    deeppink deepskyblue dimgray dodgerblue firebrick
    floralwhite forestgreen gainsboro ghostwhite gold
    goldenrod greenyellow honeydew hotpink indianred
    indigo ivory khaki lavender lavenderblush
    lawngreen lemonchiffon lightblue lightcoral lightcyan
    lightgoldenrodyellow lightgray lightgreen lightpink lightsalmon
    lightseagreen lightskyblue lightslategray lightsteelblue lightyellow
    limegreen linen mediumaquamarine mediumblue mediumorchid
    mediumpurple mediumseagreen mediumslateblue mediumspringgreen mediumturquoise
    mediumvioletred midnightblue mintcream mistyrose moccasin
    navajowhite oldlace olivedrab orange orangered
    orchid palegoldenrod palegreen paleturquoise palevioletred
    papayawhip peachpuff peru pink plum
    powderblue rebeccapurple rosybrown royalblue saddlebrown
    salmon sandybrown seagreen seashell sienna
    skyblue slateblue slategray snow springgreen
    steelblue tan thistle tomato turquoise
    violet wheat whitesmoke yellowgreen grey
    dimgrey darkgrey darkslategrey lightgrey lightslategrey
    slategrey

    Known Issues

    This initial drop is brittle. K9s will most likely blow up...

    1. You're running older versions of Kubernetes. K9s works best Kubernetes 1.12+.
    2. You don't have enough RBAC fu to manage your cluster.

    Disclaimer

    This is still work in progress! If there is enough interest in the Kubernetes community, we will enhance per your recommendations/contributions. Also if you dig this effort, please let us know that too!


    ATTA Girls/Boys!

    K9s sits on top of many of opensource projects and libraries. Our sincere appreciations to all the OSS contributors that work nights and weekends to make this project a reality!


    Meet The Core Team!