gitlab-monitor does not work with Google Cloud Memorystore
gitlab-monitor attempts to talk to the Sidekiq API, so we need to disable the CLIENT there too:
$ curl http://localhost:9168/metrics
Redis::CommandError: ERR unknown command 'client'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis/client.rb:121:in `call'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis/client.rb:104:in `block in connect'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis/client.rb:293:in `with_reconnect'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis/client.rb:100:in `connect'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis/client.rb:364:in `ensure_connected'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis/client.rb:221:in `block in process'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis/client.rb:306:in `logging'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis/client.rb:220:in `process'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis/client.rb:120:in `call'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis.rb:862:in `block in get'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis.rb:58:in `block in synchronize'
/opt/gitlab/embedded/lib/ruby/2.5.0/monitor.rb:226:in `mon_synchronize'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis.rb:58:in `synchronize'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-3.3.5/lib/redis.rb:861:in `get'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-namespace-1.5.3/lib/redis/namespace.rb:435:in `call_with_namespace'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/redis-namespace-1.5.3/lib/redis/namespace.rb:321:in `method_missing'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/gitlab-monitor-2.19.1/lib/gitlab_monitor/sidekiq.rb:115:in `block in connected?'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/sidekiq-5.2.5/lib/sidekiq.rb:97:in `block in redis'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/connection_pool-2.2.2/lib/connection_pool.rb:65:in `block (2 levels) in with'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/connection_pool-2.2.2/lib/connection_pool.rb:64:in `handle_interrupt'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/connection_pool-2.2.2/lib/connection_pool.rb:64:in `block in with'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/connection_pool-2.2.2/lib/connection_pool.rb:61:in `handle_interrupt'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/connection_pool-2.2.2/lib/connection_pool.rb:61:in `with'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/sidekiq-5.2.5/lib/sidekiq.rb:94:in `redis'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/gitlab-monitor-2.19.1/lib/gitlab_monitor/sidekiq.rb:114:in `connected?'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/gitlab-monitor-2.19.1/lib/gitlab_monitor/sidekiq.rb:124:in `ensure_queue_job_stats_script_loaded'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/gitlab-monitor-2.19.1/lib/gitlab_monitor/sidekiq.rb:26:in `initialize'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/gitlab-monitor-2.19.1/lib/gitlab_monitor/prober.rb:15:in `new'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/gitlab-monitor-2.19.1/lib/gitlab_monitor/prober.rb:15:in `block (2 levels) in probe_all'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/gitlab-monitor-2.19.1/lib/gitlab_monitor/prober.rb:14:in `each'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/gitlab-monitor-2.19.1/lib/gitlab_monitor/prober.rb:14:in `block in probe_all'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/gitlab-monitor-2.19.1/lib/gitlab_monitor/prober.rb:13:in `each'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/gitlab-monitor-2.19.1/lib/gitlab_monitor/prober.rb:13:in `probe_all'
/opt/gitlab/embedded/lib/ruby/gems/2.5.0/gems/gitlab-monitor-2.19.1/lib/gitlab_monitor/web_exporter.rb:66:in `block (2 levels) in setup_probes