Promote A Worker Node To Master



Promoting a node

You can promote any worker node to manager status at any time. To promote a node, run the below command on the manager node-

$ docker node promote NODE


Example-

first list the node.

root@master:~# docker node ls
ID                            HOSTNAME   STATUS    AVAILABILITY   MANAGER STATUS   ENGINE VERSION
buc72h0hyo66gcilq7melh9pq *   master     Ready     Active         Leader           20.10.11
xvdyauu8t83r3udrqh6c5w8a8     worker01   Ready     Active                          20.10.11
xctiaq0n14aew1falekqybq53     worker02   Ready     Active                          20.10.11


notice the manager status of worker01 and worker02 its blank in above output. now promote the worker01 and worker02 using below command.

[email protected]master:~# docker node promote worker01 worker02
Node worker01 promoted to a manager in the swarm.
Node worker02 promoted to a manager in the swarm.
[email protected]master:~#


List down the nodes again.

root@master:~# docker node ls
ID                            HOSTNAME   STATUS    AVAILABILITY   MANAGER STATUS   ENGINE VERSION
buc72h0hyo66gcilq7melh9pq *   master     Ready     Active         Leader           20.10.11
xvdyauu8t83r3udrqh6c5w8a8     worker01   Ready     Active         Reachable        20.10.11
xctiaq0n14aew1falekqybq53     worker02   Ready     Active         Reachable        20.10.11
root@master:~# 


In the output, you can now see the MANAGER STATUS as a new column added. Now, you can run the docker node ls command on newly-promoted 2 nodes as well.

Note: Here we have promoted 2 more nodes to manager status that means now we have a total of three managers. This is because docker recommends an odd number of managers.