diff options
author | Jon Bratseth <bratseth@verizonmedia.com> | 2019-06-15 19:22:02 +0200 |
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committer | Jon Bratseth <bratseth@verizonmedia.com> | 2019-06-15 19:22:02 +0200 |
commit | 0cf99d39c5fe547bda186112f9d7e2924305d45c (patch) | |
tree | 4f966cd9779285db840d5a1868decfb7d0d48b95 /node-repository | |
parent | 0de2f80d8931e59b88c0add703a71bd204e0a619 (diff) |
Add a comment warning about serialization format changes
Diffstat (limited to 'node-repository')
-rw-r--r-- | node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/LoadBalancerSerializer.java | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/LoadBalancerSerializer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/LoadBalancerSerializer.java index a4b915a6128..fd2294c1b5d 100644 --- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/LoadBalancerSerializer.java +++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/LoadBalancerSerializer.java @@ -27,6 +27,13 @@ import java.util.function.Function; */ public class LoadBalancerSerializer { + // 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 idField = "id"; private static final String hostnameField = "hostname"; private static final String dnsZoneField = "dnsZone"; |