Version 1.16. This version is no longer supported. For information about how to upgrade to version 1.28, seeUpgrade clustersin the latest documentation. For more information about supported and unsupported versions, see theVersioningpage in the latest documentation.
Distributed Cloud uses certificates and private keys to authenticate and encrypt
connections between system components in clusters. The cluster certificate
authority (CA) manages these certificates and keys. When you run thebmctl update credentials certificate-authorities rotatecommand,
Google Distributed Cloud performs the following actions:
Creates and uploads new cluster certificate authorities (CAs) for the
cluster CA, the etcd CA, and the front-proxy CA to the user cluster
namespace in the admin cluster.
The admin cluster controllers replace the user cluster certificate
authorities with the newly generated ones.
The admin cluster controllers distribute the new public CA certificates and
leaf certificate key pairs to user cluster system components.
To maintain secure cluster communication, rotate your user cluster CA
periodically and whenever there is a possible security breach.
Before you begin
Before you rotate your cluster's certificate authority, plan according to the
following conditions and impacts:
Ensure admin and user clusters are at version 1.9.0 or higher before
starting the CA rotation.
CA rotation is incremental, allowing system components to communicate during
the rotation.
The CA rotation process restarts the API server, control plane processes,
and pods in the user cluster.
Expect workloads to restart and be rescheduled during CA rotation.
For non-high-availability cluster configurations, expect brief periods of
control plane downtime during CA rotation.
Cluster management operations aren't allowed during CA rotation.
CA rotation duration depends on the size of your cluster. For example, CA
rotation may take close to two hours to complete for a cluster with one
control plane and 50 worker nodes.
Limitations
The certificate authority rotation capability has the
following limitations:
CA rotation doesn't update certificates issued manually by an administrator,
even if the cluster CA signs the certificates. Update and redistribute any
manually issued certificates after user cluster CA rotation is complete.
Once started, CA rotation can't be paused or rolled back.
Start a cluster CA rotation
Use the following command to start the CA rotation process:
CLUSTER_NAME: the name of the cluster for which you
want to rotate CAs.
KUBECONFIG: the path to the admin cluster
kubeconfig file. For self-managing clusters, this file is the cluster's
kubeconfig file.
Thebmctlcommand exits after the CA is rotated successfully and a new
kubeconfig file is generated. The standard path for the kubeconfig file isbmctl-workspace/CLUSTER_NAME/CLUSTER_NAME-kubeconfig.
Troubleshoot a cluster CA rotation
Thebmctl update credentialscommand displays the progress of the CA rotation.
The associatedupdate-credentials.logfile is saved to the following
timestamped directory:
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[[["\u003cp\u003eCluster Certificate Authority (CA) rotation is essential for maintaining secure communication within Distributed Cloud clusters and should be done periodically or after a security breach.\u003c/p\u003e\n"],["\u003cp\u003eThe \u003ccode\u003ebmctl update credentials certificate-authorities rotate\u003c/code\u003e command initiates the CA rotation process, generating new CAs for the cluster, etcd, and front-proxy, which the system then distributes to user cluster components.\u003c/p\u003e\n"],["\u003cp\u003eDuring CA rotation, system components and workloads in the user cluster will restart and be rescheduled, and there may be brief control plane downtime for non-high-availability configurations, but no management operations are permitted.\u003c/p\u003e\n"],["\u003cp\u003eCA rotation is an incremental process that can take up to two hours for large clusters and can not be paused or rolled back, so you should make sure that the clusters are at version 1.9.0 or higher before starting it.\u003c/p\u003e\n"],["\u003cp\u003eManually issued certificates are not updated by CA rotation and must be manually renewed and redistributed afterward, and expired cluster certificates need manual renewal to regain cluster functionality.\u003c/p\u003e\n"]]],[],null,["# Rotate certificate authorities\n\n\u003cbr /\u003e\n\nDistributed Cloud uses certificates and private keys to authenticate and encrypt\nconnections between system components in clusters. The cluster certificate\nauthority (CA) manages these certificates and keys. When you run the\n`bmctl update credentials certificate-authorities rotate` command,\nGoogle Distributed Cloud performs the following actions:\n\n- Creates and uploads new cluster certificate authorities (CAs) for the\n cluster CA, the etcd CA, and the front-proxy CA to the user cluster\n namespace in the admin cluster.\n\n- The admin cluster controllers replace the user cluster certificate\n authorities with the newly generated ones.\n\n- The admin cluster controllers distribute the new public CA certificates and\n leaf certificate key pairs to user cluster system components.\n\nTo maintain secure cluster communication, rotate your user cluster CA\nperiodically and whenever there is a possible security breach.\n| **Important:** If your cluster certificates have expired, you must renew them manually to regain cluster operation. For more information and instructions, see [Renew expired cluster certificates manually](/anthos/clusters/docs/bare-metal/1.16/troubleshooting/expired-certs).\n\nBefore you begin\n----------------\n\nBefore you rotate your cluster's certificate authority, plan according to the\nfollowing conditions and impacts:\n\n- Ensure admin and user clusters are at version 1.9.0 or higher before\n starting the CA rotation.\n\n- CA rotation is incremental, allowing system components to communicate during\n the rotation.\n\n- The CA rotation process restarts the API server, control plane processes,\n and pods in the user cluster.\n\n- Expect workloads to restart and be rescheduled during CA rotation.\n\n- For non-high-availability cluster configurations, expect brief periods of\n control plane downtime during CA rotation.\n\n- Cluster management operations aren't allowed during CA rotation.\n\n- CA rotation duration depends on the size of your cluster. For example, CA\n rotation may take close to two hours to complete for a cluster with one\n control plane and 50 worker nodes.\n\nLimitations\n-----------\n\nThe certificate authority rotation capability has the\nfollowing limitations:\n\n- CA rotation doesn't update certificates issued manually by an administrator,\n even if the cluster CA signs the certificates. Update and redistribute any\n manually issued certificates after user cluster CA rotation is complete.\n\n- Once started, CA rotation can't be paused or rolled back.\n\nStart a cluster CA rotation\n---------------------------\n\nUse the following command to start the CA rotation process: \n\n bmctl update credentials certificate-authorities rotate --cluster \u003cvar translate=\"no\"\u003eCLUSTER_NAME\u003c/var\u003e \\\n --kubeconfig \u003cvar translate=\"no\"\u003eKUBECONFIG\u003c/var\u003e\n\nReplace the following:\n\n- \u003cvar translate=\"no\"\u003eCLUSTER_NAME\u003c/var\u003e: the name of the cluster for which you want to rotate CAs.\n- \u003cvar translate=\"no\"\u003eKUBECONFIG\u003c/var\u003e: the path to the admin cluster kubeconfig file. For self-managing clusters, this file is the cluster's kubeconfig file.\n\nThe `bmctl` command exits after the CA is rotated successfully and a new\nkubeconfig file is generated. The standard path for the kubeconfig file is\n`bmctl-workspace/`\u003cvar translate=\"no\"\u003eCLUSTER_NAME\u003c/var\u003e`/`\u003cvar translate=\"no\"\u003eCLUSTER_NAME\u003c/var\u003e`-kubeconfig`.\n\nTroubleshoot a cluster CA rotation\n----------------------------------\n\nThe `bmctl update credentials` command displays the progress of the CA rotation.\nThe associated `update-credentials.log` file is saved to the following\ntimestamped directory:\n\n`bmctl-workspace/`\u003cvar translate=\"no\"\u003eCLUSTER_NAME\u003c/var\u003e`/log/update-credentials-`\u003cvar translate=\"no\"\u003eTIMESTAMP\u003c/var\u003e"]]
