diff options
Diffstat (limited to 'node-repository')
2 files changed, 11 insertions, 4 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"; diff --git a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializer.java b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializer.java index d38a6e5031c..424889caf72 100644 --- a/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializer.java +++ b/node-repository/src/main/java/com/yahoo/vespa/hosted/provision/persistence/NodeSerializer.java @@ -44,12 +44,12 @@ import java.util.function.UnaryOperator; */ public class NodeSerializer { - // WARNING: Since there are multiple config servers in a 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: + // 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. /** The configured node flavors */ private final NodeFlavors flavors; |