You installed CrateDB using the apt packages, correct?
If you do that, CrateDB starts automatically ins single-node
mode which also prevents adding the nodes to any sort of cluster. This is intentional in a way, that apt packages should start without any additional confiuguration.
There are basically two ways to fix this
- using the
crate-node
tool
or (easier)
- deleting the cluster state by …
service crate stop
rm -rf /usr/share/crate/data
service crate start