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Using the Rancher CLI

In addition to the Rancher GUI, your software in Spin can also be managed via the Rancher CLI, using a tool called rancher. You might already be familiar with the native Kubernetes CLI tool kubectl, which is actually used by the rancher kubectl subcommand. However, kubectl by itself will not work with Spin due to security and Role Based Access Controls (RBAC) built into Rancher.

Tip

These CLI tools are general purpose tools and have options which cannot be used with Spin. If you try these options, you should see an error message such as "Access Denied".

Accessing the tool

There are two ways to use the Rancher CLI: From a NERSC login node such as cori.nersc.gov & spin.nersc.gov, or from your laptop.

Either way, you will need to obtain an API key from the Rancher GUI and store it for use with the CLI.

Using the CLI from cori/spin.nersc.gov

Log into a login node, and load the Spin 2 module:

stefanl@spin:~ $ module load spin/2.0
stefanl@spin:~ $ which rancher
/global/common/shared/isg/spin/2.0/bin/rancher
stefanl@spin:~ $ rancher --version
rancher version v2.4.3
stefanl@spin:~ $ 

Then, proceed with obtaining your API credentials below.

Using the CLI from your laptop

You will need:

  1. An operating system with a good command-line terminal, such as macOS, Linux, or Windows 10 with WSL2.
  2. An account on Spin.
  3. The kubectl CLI. This is normally provided by Docker for Mac and Docker for Windows, or from the standard package management system on Linux.
  4. The rancher CLI. This can be downloaded by logging into https://rancher2.spin.nersc.gov and download the CLI from the bottom right corner.

Both rancher & kubectl must be in your $PATH.

Warning about versions in Docker for Mac, Docker for Windows, Linux & your self-maintained verisons

If you use Docker for Mac, vendor packages, Ubuntu Snap, etc. Keep an eye on the version of kubectl provided by these vendors-- kubectl may get updated without your knowledge, which can lead to incompatibilities.

The kubectl CLI must be within one minor version of the Kubernetes server version. That is, if the Kubernetes cluster runs 1.17.x, your CLI must be version 1.16 - 1.18.

Run kubectl version --short to see the versions:

$ kubectl version --short
Client Version: v1.17.3
Server Version: v1.16.8

Kubernetes has a fast upgrade cycle, and we must stay up to date. NERSC updates Kubernetes on the server to a new minor version (i.e The 1.x version) at least twice per year. For example, during 2021 we will upgrade from 1.17 to 1.18 to 1.19 to stay on a supported version.

Keep these tools up to date

The rancher & kubectl CLIs are updated at least once per quarter. You are responsible for keeping the software up to date on your own system.

Generate the API credentials & login

Security Note

These API keys give full control to everything within your Project & Namespaces. Guard them well.

Notice

The UI will only provide one opportunity to copy the credentials, and you will not be able to retrieve the credentials if you close the window. However, you can always delete and recreate the credentials.

You will need:

  1. A terminal window which is logged into a NERSC login node, or a terminal window open on your laptop
  2. A working Rancher CLI

First, we will generate the API Key (token):

  1. Login to https://rancher2.spin.nersc.gov/
  2. Browse to the API credential menu at User Icon (Upper right) -> API & Keys -> API Key
  3. Create a key with the following settings

    • Automatically Expire -> 1 year from now. If you're just testing, set the expiration to be 1 month from now. (Expiration dates are good for security)
    • Name = Whatever (Pro Tip: Put the expiration date in the name)
    • Leave Scope as "no scope" (Important)
    • Hit the Create button
    • You are now at a window that says "API Key Created"
    • Don't close this window until you have saved the key
    • Make note of the important fields Endpoint: and Bearer Token:
      • Ignore the fields Access Key (username) and Secret Key (password). They are combined into the Bearer Token.
    • Keep the window open for now

Now, head over to your terminal window, and use the API Key to log into Rancher. Use the values of the Endpoint (Including the /v3 at the end) and Bearer Token (including the part before and after the :), like so:

rancher login --token <Bearer Token> <Endpoint URL>

You will see something similar to this:

stefanl@spin:~ $ rancher login --token a1b2c3:AAAABBBBCCCCDDDDEEEE https://rancher2.spin.nersc.gov/v3
INFO[0000] Only 1 project available: spinup
INFO[0000] Saving config to /global/homes/s/stefanl/.rancher/cli2.json
stefanl@spin:~ $

And now, test that your token is valid. You will see a list of projects that you have access too:

stefanl@spin:~ $ rancher project
ID                NAME      STATE     DESCRIPTION
c-fwj56:p-6q5dd   spinup    active
stefanl@spin:~ $

Rancher CLI highlights

The rancher CLI supports Rancher-specific commands as well as Kubernetes-specific subcommands via rancher kubectl. Each style of commands has its own help:

  • rancher --help for help with the Rancher-specific commands
  • rancher kubectl --help for help with the Kubernetes-specific commands.

Some examples are:

  • rancher ps - Show workloads in projects
  • rancher namespaces - Create/remove/move namespaces within a project

See other Rancher CLI examples at https://rancher.com/docs/rancher/v2.x/en/cli/

Kubernetes examples would be:

  • rancher kubectl apply -f my-deployment.yml - Update a Kubernetes resource with the configuration specified in my-deployment.yaml.
  • rancher kubectl annotate ... - Apply an annotation to a Kubernetes resource

See other Kubectl examples at https://kubernetes.io/docs/reference/kubectl/overview/ . Remember these must all called as rancher kubectl.

Advanced

Multiple projects

If you have multiple projects (also called "contexts"), Rancher will prompt you to select a context:

stefanl@spin:~ $ rancher login https://rancher2.spin.nersc.gov/v3 --token token-lsw5b:123468734878473897189789127389127
NUMBER    CLUSTER NAME   PROJECT ID        PROJECT NAME   PROJECT DESCRIPTION
1         development    c-fwj56:p-2tlth   stefanl        
2         development    c-fwj56:p-4qjxn   spintest       
Select a Project:

More than one token? Use --name

stefanl@spin:~ $ rancher login --name foo --token token-nql59:lkasjdklsljaskldjaskljasdljsa https://rancher2.spin.nersc.gov/v3
INFO[0000] Only 1 project available: spinup
INFO[0000] Saving config to /global/homes/s/stefanl/.rancher/cli2.json
stefanl@spin:~ $
To see multiple tokens
stefanl@spin:~ $ cat /global/homes/s/stefanl/.rancher/cli2.json  | jq
{
  "Servers": {
      "foo": {
      "accessKey": "token-EFG59",
      "secretKey": "lkasjdklsljaskldjaskljasdljsa",
      "tokenKey": "token-nql59:lkasjdklsljaskldjaskljasdljsa",
      "url": "https://rancher2.spin.nersc.gov",
      "project": "c-fwj56:p-6q5dd",
      "cacert": ""
    },
    "rancherDefault": {
      "accessKey": "token-ABC79",
      "secretKey": "lkasjdklsljaskldjaskljasdljsa",
      "tokenKey": "token-nql59:lkasjdklsljaskldjaskljasdljsa",
      "url": "https://rancher2.spin.nersc.gov",
      "project": "c-fwj56:p-6q5dd",
      "cacert": ""
    }
  },
  "CurrentServer": "foo"
}
stefanl@spin:~ $