The Kubernetes command-line interface (CLI), cfssl, is a tool that enables users to operate a Kubernetes cluster from the command line. This article provides an overview of how to install and set up the cfssl tool, and how to use it to manage a Kubernetes cluster.
The Cfssl tool can be installed on any Linux or macOS system. To install cfssl on Linux, use the following command:
$ curl -LO https://storage.googleapis.com/kubernetes-release/cfssl/cfssl_linux-amd64.tar.gz
$ tar -xzf cfssl_linux-amd64.tar.gz
$ mv cfssl_linux-amd64/bin/cfssl /usr/local/bin/
$ rm -rf cfssl_linux-amd64
To install cfssl on macOS, use the following command:
$ brew install cfssl
Once you have installed the cfssl tool, you need to set up your environment variables. The CFSSL_CA environment variable specifies the path to the CA certificate used by cfssl. The CFSSL_CERT environment variable specifies the path to the client certificate used by cfssl. The CFSSL_KEY environment variable specifies the path to the client key used by cfssl.
To set up the cfssl tool, use the following commands:
$ export CFSSL_CA=/path/to/ca.pem
$ export CFSSL_CERT=/path/to/client.pem
$ export CFSSL_KEY=/path/to/client-key.pem
Once you have installed and set up the cfssl tool, you can use it to create a Kubernetes cluster. To create a Kubernetes cluster, use the following command:
$ cfssl create-cluster -size=3 -server=https://kubernetes.default.svc.cluster.local:443 -ca=ca.pem -ca-key=ca-key.pem
This command creates a Kubernetes cluster with three nodes. The server flag specifies the URL of the Kubernetes API server. The ca flag specifies the path to the CA certificate used by cfssl. The ca-key flag specifies the path to the CA key used by cfssl.
To delete a Kubernetes cluster, use the following command:
$ cfssl delete-cluster -name=my-cluster
This command deletes the Kubernetes cluster with the name my-cluster.
To list the Kubernetes clusters created with cfssl, use the following command:
$ cfssl list-clusters
This command lists all of the Kubernetes clusters created with cfssl.
To get information about a Kubernetes cluster, use the following command:
$ cfssl get-cluster -name=my-cluster
This command gets information about the Kubernetes cluster with the name my-cluster.
To update a Kubernetes cluster, use the following command:
$ cfssl update-cluster -name=my-cluster -size=5
This command updates the size of the Kubernetes cluster with the name my-cluster to five nodes.
To add nodes to a Kubernetes cluster, use the following command:
$ cfssl add-node -name=my-cluster -size=3
This command adds three nodes to the Kubernetes cluster with the name my-cluster.
To delete nodes from a Kubernetes cluster, use the following command:
$ cfssl delete-node -name=my-cluster -size=3
This command deletes three nodes from the Kubernetes cluster with the name my-cluster.
To scale a Kubernetes cluster, use the following command:
$ cfssl scale-cluster -name=my-cluster -size=5
This command scales the Kubernetes cluster with the name my-cluster to five nodes.
To resize a Kubernetes cluster, use the following command:
$ cfssl resize-cluster -name=my-cluster -size=3
This command resizes the Kubernetes cluster with the name my-cluster to three nodes.
To get the status of a Kubernetes cluster, use the following command:
$ cfssl get-status -name=my-cluster
This command gets the status of the Kubernetes cluster with the name my-cluster.
To get help for a particular command, use the following command:
$ cfssl help <command>
This command gets help for the cfssl command.