diff options
Diffstat (limited to 'controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/RunSerializer.java')
| -rw-r--r-- | controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/RunSerializer.java | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/RunSerializer.java b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/RunSerializer.java index f29af1055d0..1c95c9766f5 100644 --- a/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/RunSerializer.java +++ b/controller-server/src/main/java/com/yahoo/vespa/hosted/controller/persistence/RunSerializer.java @@ -56,6 +56,13 @@ import static java.util.Comparator.comparing; */ class RunSerializer { + // WARNING: Since there are multiple servers in a ZooKeeper cluster and they upgrade one by one + // (and rewrite all nodes on startup), changes to the serialized format must be made + // such that what is serialized on version N+1 can be read by version N: + // - ADDING FIELDS: Always ok + // - REMOVING FIELDS: Stop reading the field first. Stop writing it on a later version. + // - CHANGING THE FORMAT OF A FIELD: Don't do it bro. + private static final String stepsField = "steps"; private static final String applicationField = "id"; private static final String jobTypeField = "type"; |