diff options
Diffstat (limited to 'config-provisioning/src/main/java/com/yahoo/config/provision/AllocatedHosts.java')
| -rw-r--r-- | config-provisioning/src/main/java/com/yahoo/config/provision/AllocatedHosts.java | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/config-provisioning/src/main/java/com/yahoo/config/provision/AllocatedHosts.java b/config-provisioning/src/main/java/com/yahoo/config/provision/AllocatedHosts.java index de4f3a555bd..96942c53a12 100644 --- a/config-provisioning/src/main/java/com/yahoo/config/provision/AllocatedHosts.java +++ b/config-provisioning/src/main/java/com/yahoo/config/provision/AllocatedHosts.java @@ -26,6 +26,13 @@ import java.util.Set; */ public class AllocatedHosts { + // 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 mappingKey = "mapping"; private static final String hostSpecKey = "hostSpec"; private static final String hostSpecHostNameKey = "hostName"; |