SSH access to a worker node

In order to SSH into a worker node, you first have to find the external IP address of the node:

$ kubectl get nodes -o wide
NAME                          STATUS    ROLES     AGE       VERSION   EXTERNAL-IP       OS-IMAGE             KERNEL-VERSION      CONTAINER-RUNTIME
metakube-fhgbvx12xg-4kmht     Ready     <none>    1d        v1.10.3   123.123.123.1     Ubuntu 16.04.4 LTS   4.4.0-116-generic   docker://17.3.2
metakube-fhgbvx12xg-jzspq     Ready     <none>    1d        v1.10.3   123.123.123.2     Ubuntu 16.04.4 LTS   4.4.0-116-generic   docker://17.3.2
metakube-fhgbvx12xg-t8nwc     Ready     <none>    1d        v1.10.3   123.123.123.3     Ubuntu 16.04.4 LTS   4.4.0-116-generic   docker://17.3.2

You can use the external IP to ssh into the node using the SSH key you added as described in add an SSH key:

ssh -i ~/.ssh/id_rsa ubuntu@123.123.123.1

The default username depends on the used operating system, for a complete list see Supported Operating Systems.