diff options
Diffstat (limited to 'doc/administration/high_availability/consul.md')
| -rw-r--r-- | doc/administration/high_availability/consul.md | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/doc/administration/high_availability/consul.md b/doc/administration/high_availability/consul.md index b01419200cc..392b9b76c31 100644 --- a/doc/administration/high_availability/consul.md +++ b/doc/administration/high_availability/consul.md @@ -102,6 +102,23 @@ To be safe, we recommend you only restart one server agent at a time to ensure t For larger clusters, it is possible to restart multiple agents at a time. See the [Consul consensus document](https://www.consul.io/docs/internals/consensus.html#deployment-table) for how many failures it can tolerate. This will be the number of simulateneous restarts it can sustain. +## Upgrades for bundled Consul + +Nodes running GitLab-bundled Consul should be: + +- Members of a healthy cluster prior to upgrading the GitLab Omnibus package. +- Upgraded one node at a time. + +NOTE: **NOTE:** +Running `curl http://127.0.0.1:8500/v1/health/state/critical` from any Consul node will identify existing health issues in the cluster. The command will return an empty array if the cluster is healthy. + +Consul clusters communicate using the raft protocol. If the current leader goes offline, there needs to be a leader election. A leader node must exist to facilitate synchronization across the cluster. If too many nodes go offline at the same time, the cluster will lose quorum and not elect a leader due to [broken consensus](https://www.consul.io/docs/internals/consensus.html). + +Consult the [troubleshooting section](#troubleshooting) if the cluster is not able to recover after the upgrade. The [outage recovery](#outage-recovery) may be of particular interest. + +NOTE: **NOTE:** +GitLab only uses Consul to store transient data that is easily regenerated. If the bundled Consul was not used by any process other than GitLab itself, then [rebuilding the cluster from scratch](#recreate-from-scratch) is fine. + ## Troubleshooting ### Consul server agents unable to communicate |