Cluster Status Is Unavailable

Symptom

A CSS cluster status is Unavailable.

Figure 1 Unavailable cluster

Cause Analysis and Solution

• If the task status is Frozen, see A Cluster Is Frozen and Unavailable.
• If the task status is Configuration error. Restart failed, see A Cluster Is Unavailable Due to X-pack Parameter Configuration.
• If the node log contains the error message "master not discovered or elected yet, an election requires at least 2 nodes with ids [xxx, xxx, xxx, ...], have discovered [xxx...] which is not a quorum", see A Cluster Is Unavailable Due to Improper Security Group Rules.
• If the node log contains the error message "fatal error in thread [main], exitingjava.lang. NoClassDefFoundError: xxx/xxx/.../xxxPlugin at ...", see A Cluster is Unavailable Due to Plugin Incompatibility.
• If the cluster health status is red and the value of unassigned shards is not 0, the cluster has index shards that cannot be allocated. For details, see A Cluster is Unavailable Due to Improper Shard Allocation.
• If a cluster is unavailable after being restored or migrated, see A Cluster is Unavailable Due to Incompatible Data Types.
• If the node log contains the error message "OutOfMemoryError" and warning information "[gc][xxxxx] overhead spent [x.xs] collecting in the last [x.xs]", see A Cluster is Unavailable Due to Heavy Load.