Description of change
Instead of using placement (--to) for node affinity, use constraints instead. We support zones, affinity, and anti-affinity. Anti-affinity is done by prefixing the label key with "^". Labels for a given key are separated by "|". eg juju deploy foo --constraints="tags=key1=a|b|c,^key2=c|d|e zones=z1,z2"
QA steps
bootstrap k8s and deploy a charm to a node with some labels using constraints
该提问来源于开源项目：juju/juju
