Cassandra backend: error=gocql: no hosts available in the pool

[qk4l]

Describe the bug
Vault do not restore connection with Cassandra nodes after there restart.
Then last of Cassandra node in cluster would restart Vault starts return 500 error

error="gocql: no hosts available in the pool

To Reproduce
Steps to reproduce the behavior:
1.Configure Vault to use Cassandra backend
2. Subsequence stop/start each Cassandra node in cluster based cluster availability
3. After last node stop Vault failed

Expected behavior
Vault should return Cassandra nodes to pool after there restore

Environment:

• Vault Server Version (retrieve with vault status): 1.8.4

Vault server configuration file(s):

storage "cassandra" {
   hosts            = "1.cdb.vault.example.com,2.cdb.vault.example.com,3.cdb.vault.example.com"
   consistency      = "QUORUM"
   protocol_version = "2"
   keyspace = "vault"
   username = "admin"
   password = "PASSWORD"
   connection_timeout = "10"
   simple_retry_policy_retries = "3"
}

Additional context
It's a bug in apache/cassandra-gocql-driver#915

[voltbit]

Hi @hsimon-hashicorp would it be possible for the proposed fix to make it into the next release? We would benefit from it as we have observed the same behaviour.