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Kubectl plugin

kubectl cert-manager is a kubectl plugin that can help you to manage cert-manager resources inside your cluster.

Installation

You need the kubectl-cert-manager.tar.gz file for the platform you're using, these can be found on our GitHub releases page. In order to use the kubectl plugin you need its binary to be accessible under the name kubectl-cert_manager in your $PATH. Run the following commands to set up the plugin:

$ curl -L -o kubectl-cert-manager.tar.gz https://github.com/cert-manager/cert-manager/releases/download/v1.3.1/kubectl-cert_manager-linux-amd64.tar.gz
$ tar xzf kubectl-cert-manager.tar.gz
$ sudo mv kubectl-cert_manager /usr/local/bin

You can run kubectl cert-manager help to test the plugin is set up properly:

$ kubectl cert-manager help
kubectl cert-manager is a CLI tool manage and configure cert-manager resources for Kubernetes
Usage:
kubectl cert-manager [command]
Available Commands:
convert Convert cert-manager config files between different API versions
create Create cert-manager resources
help Help about any command
renew Mark a Certificate for manual renewal
status Get details on current status of cert-manager resources
version Print the kubectl cert-manager version
Flags:
--as string Username to impersonate for the operation
--as-group stringArray Group to impersonate for the operation, this flag can be repeated to specify multiple groups.
--cache-dir string Default cache directory (default "~/.kube/cache")
--certificate-authority string Path to a cert file for the certificate authority
--client-certificate string Path to a client certificate file for TLS
--client-key string Path to a client key file for TLS
--cluster string The name of the kubeconfig cluster to use
--context string The name of the kubeconfig context to use
-h, --help help for cert-manager
--insecure-skip-tls-verify If true, the server's certificate will not be checked for validity. This will make your HTTPS connections insecure
--kubeconfig string Path to the kubeconfig file to use for CLI requests.
--log-flush-frequency duration Maximum number of seconds between log flushes (default 5s)
--match-server-version Require server version to match client version
-n, --namespace string If present, the namespace scope for this CLI request
--request-timeout string The length of time to wait before giving up on a single server request. Non-zero values should contain a corresponding time unit (e.g. 1s, 2m, 3h). A value of zero means don't timeout requests. (default "0")
-s, --server string The address and port of the Kubernetes API server
--tls-server-name string Server name to use for server certificate validation. If it is not provided, the hostname used to contact the server is used
--token string Bearer token for authentication to the API server
--user string The name of the kubeconfig user to use
Use "kubectl cert-manager [command] --help" for more information about a command.

Commands

Renew

Note: for cert-manager v0.15 this feature requires the ExperimentalCertificateControllers feature gate set. From cert-manager v0.16 onward, the experimental certificate controller is the default.

kubectl cert-manager renew allows you to manually trigger a renewal of a specific certificate. This can be done either one certificate at a time, using label selectors (-l app=example), or with the --all flag:

For example you can renew the certificate example-com-tls:

$ kubectl get certificate
NAME READY SECRET AGE
example-com-tls True example-com-tls 1d
$ kubectl cert-manager renew example-com-tls
Manually triggered issuance of Certificate default/example-com-tls
$ kubectl get certificaterequest
NAME READY AGE
example-com-tls-tls-8rbv2 False 10s

You can also renew all certificates in a given namespace:

$ kubectl cert-manager renew --namespace=app --all

The renew command allows several options to be specified:

  • --all renew all Certificates in the given Namespace, or all namespaces when combined with --all-namespaces
  • -A or --all-namespaces mark Certificates across namespaces for renewal
  • -l --selector allows set a label query to filter on as well as kubectl global flags like --context and --namespace.

Convert

kubectl cert-manager convert can be used to convert cert-manager manifest files between different API versions. Both YAML and JSON formats are accepted. The command takes file name, directory, or URL as input, and converts into the format of the latest version or the one specified by --output-version flag.

The default output will be printed to stdout in YAML format. One can use -o option to change the output destination.

For example this will output cert.yaml in the latest API version:

kubectl cert-manager convert -f cert.yaml

Create

kubectl cert-manager create can be used to create cert-manager resources manually. Sub-commands are available to create different resources:

CertificateRequest

To create a cert-manager CertificateRequest, use kubectl cert-manager create certificaterequest. The command takes in the name of the CertificateRequest to be created, and creates a new CertificateRequest resource based on the YAML manifest of a Certificate resource as specified by --from-certificate-file flag, by generating a private key locally and creating a 'certificate signing request' to be submitted to a cert-manager Issuer. The private key will be written to a local file, where the default is <name_of_cr>.key, or it can be specified using the --output-key-file flag.

If you wish to wait for the CertificateRequest to be signed and store the X.509 certificate in a file, you can set the --fetch-certificate flag. The default timeout when waiting for the issuance of the certificate is 5 minutes, but can be specified with the --timeout flag. The default name of the file storing the X.509 certificate is <name_of_cr>.crt, you can use the --output-certificate-file flag to specify otherwise.

Note that the private key and the X.509 certificate are both written to file, and are not stored inside Kubernetes.

For example this will create a CertificateRequest resource with the name "my-cr" based on the cert-manager Certificate described in my-certificate.yaml while storing the private key and X.509 certificate in my-cr.key and my-cr.crt respectively.

kubectl cert-manager create certificaterequest my-cr --from-certificate-file my-certificate.yaml --fetch-certificate --timeout 20m

Status Certificate

kubectl cert-manager status certificate outputs the details of the current status of a Certificate resource and related resources like CertificateRequest, Secret, Issuer, as well as Order and Challenges if it is a ACME Certificate. The command outputs information about the resources, including Conditions, Events and resource specific fields like Key Usages and Extended Key Usages of the Secret or Authorizations of the Order. This will be helpful for troubleshooting a Certificate.

The command takes in one argument specifying the name of the Certificate resource and the namespace can be specified as usual with the -n or --namespace flag.

This example queries the status of the Certificate named my-certificate in namespace my-namespace.

kubectl cert-manager status certificate my-certificate -n my-namespace

Approve/Deny

CertificateRequests can be approved or denied using their respective kubectl plugin commands:

Note: The internal cert-manager approver may automatically approve all CertificateRequests unless disabled with the flag on the cert-manager-controller --controllers=*,-certificaterequests-approver

$ kubectl cert-manager approve -n istio-system mesh-ca --reason "pki-team" --message "this certificate is valid"
Approved CertificateRequest 'istio-system/mesh-ca'
$ kubectl cert-manager deny -n my-app my-app --reason "example.com" --message "violates policy"
Denied CertificateRequest 'my-app/my-app'