Minimal downtime when rebooting etcd nodes

Graceful leader changes When needing to restart some Kubernetes control-plane nodes on which etcd also happens to be running, you will prefer a graceful transfer of the leadership of the etcd cluster, to reduce the transition period that comes with a leader election. This can be achieved with the following script, provided you specify the adequate environment variables in /etc/profile.d/etcd-all file. set -o pipefail && \ source /etc/profile.d/etcd-all && \ AM_LEADER=$(etcdctl endpoint status | grep $(hostname) | cut -d ',' -f 5 | tr -d ' ') && \ if [[ $AM_LEADER = "true" ]] then NEW_LEADER=$(etcdctl endpoint status | grep -v $(hostname) | cut -d ',' -f 2 | tr -d ' ' | tail -n '-1') && \ etcdctl move-leader $NEW_LEADER && sleep 15 fi Info: the following environment variables need to be set, for example through a file such as: /etc/profile.d/etcd-all ...

7 July 2023 · 1 min · 154 words · Clément Nussbaumer