v21.03.31

Changelog

549c0f7 Revert "workload id will be returned as the first message (#364)"
6e5e014 add err handling, avoid panic (#374)
84f4705 add error for node set down (#359)
9759655 add trylock for mutex
8902e3b bugfix: doRemoveWorkload isn't for rollback of deploy (#368)
ab9cb9f bugfix: fix nil store in tests
5914b8f enable redis as store
6d5814b fix: make golint works (#373)
7624030 fix: wal deadlock (#375)
feaf46d make mock engine rework again
a2ba499 redis as broker (#369)
4bb9861 remove external redis dependency for testing (#371)
41c527b support excluding nodes when creating workloads (#365)
c90580c support ulimit for docker engine #362
789ca9d to remove ctx which unused (#372)
5399d07 wider coverage of error stack (#358)
f87a4b0 workload id will be returned as the first message (#364)