[infinispan-issues] [Red Hat JIRA] (ISPN-12235) Perform multicast test on startup

Perform multicast test on startup --------------------------------- Key: ISPN-12235 URL: https://issues.redhat.com/browse/ISPN-12235 Project: Infinispan Issue Type: Feature Request Components: Core Affects Versions: 11.0.3.Final Reporter: Dan Berindei Priority: Major Fix For: 12.1.0.Final UDP and IP multicast in particular are not reliable in some environments. E.g. * In our test environment datagrams bigger than 9KB are sometimes dropped, causing poor performance. * In some IPv6 environments datagrams bigger than the MTU are dropped instead of being fragmented when receiving a ICMP 4 "The datagram is too big. Packet fragmentation is required but the 'don't fragment' (DF) flag is on." packet. * Multicast groups sometimes disappear [with IGMP snooping enabled|https://access.redhat.com/solutions/22169]. Users can diagnose these problems by using JGroups' {{McastSenderTest}} and {{McastReceiverTest}} on all the nodes, but it's a manual process, and it requires an investigation to know that the network might have a problem. This kind of issue first appears in the log as a generic timeout error, e.g. {noformat} org.infinispan.commons.CacheException: Initial state transfer timed out for cache org.infinispan.CONFIG on Node at org.infinispan.statetransfer.StateTransferManagerImpl.waitForInitialStateTransferToComplete(StateTransferManagerImpl.java:246) {noformat} We should try to help the user by send a big multicast message at the beginning and failing if we don't get responses from all other members. An alternative would be to expose a multicast test as a Console/CLI operation and invoking it automatically when a diagnostic report is generated.