github.com/coreos/rocket@v1.30.1-0.20200224141603-171c416fac02/Documentation/upgrading.md (about)

     1  ## Upgrading rkt
     2  
     3  Usually, upgrading rkt should work without doing anything special: pods started with the old version will continue running and new pods will be started with the new version.
     4  However, in some cases special care must be taken.
     5  
     6  ### When the rkt api-service is running
     7  
     8  If the api-service is running and the new version of rkt does a store version upgrade that requires migration, new invocations of rkt will be blocked.
     9  This is so because the api-service is a long running process that holds a lock on the store, and the store migration needs to take an exclusive lock on it.
    10  
    11  For this reason, it is recommended to stop the api-service and start the latest version when upgrading rkt.
    12  
    13  This recommendation doesn't apply if the new api-service is listening on a different port and using a different [rkt data directory](commands.md#global-options) via the `--dir` flag.