docker/dtr emergency-repairEstimated reading time: 3 minutes
This topic applies to Docker Enterprise.
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Recover DTR from loss of quorum
docker run -it --rm docker/dtr \ emergency-repair [command options]
This command repairs a DTR cluster that has lost quorum by reverting your cluster to a single DTR replica.
There are three steps you can take to recover an unhealthy DTR cluster:
- If the majority of replicas are healthy, remove the unhealthy nodes from the cluster, and join new ones for high availability.
- If the majority of replicas are unhealthy, use this command to revert your cluster to a single DTR replica.
- If you can’t repair your cluster to a single replica, you’ll have to
restore from an existing backup, using the
When you run this command, a DTR replica of your choice is repaired and
turned into the only replica in the whole DTR cluster.
The containers for all the other DTR replicas are stopped and removed. When
force option, the volumes for these replicas are also deleted.
After repairing the cluster, you should use the
join command to add more
DTR replicas for high availability.
||$DEBUG||Enable debug mode for additional logs.|
||$DTR_REPLICA_ID||The ID of an existing DTR replica. To add, remove or modify DTR, you must connect to an existing healthy replica’s database.|
||$DTR_EXTENDED_HELP||Display extended help text for a given command.|
||$DTR_OVERLAY_SUBNET||The subnet used by the dtr-ol overlay network. Example:
||$PRUNE||Delete the data volumes of all unhealthy replicas. With this option, the volume of the DTR replica you’re restoring is preserved but the volumes for all other replicas are deleted. This has the same result as completely uninstalling DTR from those replicas.|
||$UCP_CA||Use a PEM-encoded TLS CA certificate for UCP. Download the UCP TLS CA certificate from https://
||$UCP_INSECURE_TLS||Disable TLS verification for UCP. The installation uses TLS but always trusts the TLS certificate used by UCP, which can lead to MITM (man-in-the-middle) attacks. For production deployments, use
||$UCP_PASSWORD||The UCP administrator password.|
||$UCP_URL||The UCP URL including domain and port.|
||$UCP_USERNAME||The UCP administrator username.|
||$YES||Answer yes to any prompts.|