# Adding arbiter to existing cluster **URL:** \ **Category:** Percona XtraDB Cluster 8.x\ **Created:** [November 10, 2020, 8:05am UTC](https://forums.percona.com/t/adding-arbiter-to-existing-cluster/8258 "2020-11-10T08:05:32Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Cihan\_Tunali](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/cihan_tunali/32/4574_2.png) [@Cihan\_Tunali](https://forums.percona.com/u/Cihan_Tunali)\ **Post date:** [November 10, 2020, 8:05am UTC](https://forums.percona.com/t/adding-arbiter-to-existing-cluster/8258/1 "2020-11-10T08:05:32Z")
Hello all, I have 3 node xtradb cluster and want to add arbiter to that cluster. I followed “[https://www.percona.com/doc/percona-xtradb-cluster/8.0/howtos/garbd\_howto.html](https://www.percona.com/doc/percona-xtradb-cluster/8.0/howtos/garbd_howto.html)” this article, but arbiter could not communicate even it has network connectivity. What am i missing? Arbiter log: 2020-11-10 16:26:45.537 INFO: CRC-32C: using hardware acceleration. 2020-11-10 16:26:45.537 INFO: Read config: ``` daemon: 0 name: garb address: gcomm://10.10.10.201:4567,10.10.10.202:4567,10.10.10.203:4567 group: pxc-poc sst: trivial donor: options: gcs.fc_limit=9999999; gcs.fc_factor=1.0; gcs.fc_master_slave=yes cfg: log: recv_script: ``` 2020-11-10 16:26:45.539 INFO: protonet asio version 0 2020-11-10 16:26:45.539 INFO: Using CRC-32C for message checksums. 2020-11-10 16:26:45.539 INFO: backend: asio 2020-11-10 16:26:45.539 INFO: gcomm thread scheduling priority set to other:0 2020-11-10 16:26:45.540 WARN: Fail to access the file (./gvwstate.dat) error (No such file or directory). It is possible if node is booting for first time or re-booting after a graceful shutdown 2020-11-10 16:26:45.540 INFO: Restoring primary-component from disk failed. Either node is booting for first time or re-booting after a graceful shutdown 2020-11-10 16:26:45.540 INFO: GMCast version 0 2020-11-10 16:26:45.540 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) listening at tcp://0.0.0.0:4567 2020-11-10 16:26:45.541 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) multicast: , ttl: 1 2020-11-10 16:26:45.541 INFO: EVS version 1 2020-11-10 16:26:45.541 INFO: gcomm: connecting to group ‘pxc-poc’, peer ‘10.10.10.201:4567,10.10.10.202:4567,10.10.10.203:4567’ 2020-11-10 16:26:48.543 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.201:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:26:48.543 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.202:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:26:48.543 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.203:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:26:48.543 INFO: announce period timed out (pc.announce\_timeout) 2020-11-10 16:26:48.543 INFO: EVS version upgrade 0 → 1 2020-11-10 16:26:48.543 INFO: PC protocol upgrade 0 → 1 2020-11-10 16:26:48.543 WARN: no nodes coming from prim view, prim not possible 2020-11-10 16:26:48.543 INFO: Current view of cluster as seen by this node view (view\_id(NON\_PRIM,60f0857d,1) memb { ``` 60f0857d,0 } ``` joined { ``` } ``` left { ``` } ``` partitioned { ``` } ``` ) 2020-11-10 16:26:49.043 WARN: last inactive check more than PT1.5S (3\*evs.inactive\_check\_period) ago (PT3.50246S), skipping check 2020-11-10 16:26:52.544 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.201:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:26:55.544 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.202:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:26:58.545 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.201:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:27:01.545 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.202:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:27:04.546 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.201:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:27:07.547 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.202:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:27:10.547 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.201:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:27:13.548 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.202:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:27:16.548 INFO: (60f0857d, ‘tcp://0.0.0.0:4567’) connection to peer 00000000 with addr tcp://10.10.10.201:4567 timed out, no messages seen in PT3S (gmcast.peer\_timeout) 2020-11-10 16:27:18.556 INFO: PC protocol downgrade 1 → 0 2020-11-10 16:27:18.556 INFO: Current view of cluster as seen by this node view ((empty)) 2020-11-10 16:27:18.556 ERROR: failed to open gcomm backend connection: 110: failed to reach primary view (pc.wait\_prim\_timeout): 110 (Connection timed out) ``` at gcomm/src/pc.cpp:connect():159 ``` 2020-11-10 16:27:18.556 ERROR: gcs/src/gcs\_core.cpp:gcs\_core\_open():220: Failed to open backend connection: -110 (Connection timed out) 2020-11-10 16:27:18.556 ERROR: gcs/src/gcs.cpp:gcs\_open():1700: Failed to open channel ‘pxc-poc’ at ‘gcomm://10.10.10.201:4567,10.10.10.202:4567,10.10.10.203:4567’: -110 (Connection timed out) 2020-11-10 16:27:18.556 FATAL: Exception in creating receive loop: Failed to open connection to group: 110 (Connection timed out) ``` at garb/garb_gcs.cpp:Gcs():35 ``` ---
**Author:** ![matthewb](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/matthewb/32/34_2.png) [@matthewb](https://forums.percona.com/u/matthewb)\ **Post date:** [November 11, 2020, 12:40pm UTC](https://forums.percona.com/t/adding-arbiter-to-existing-cluster/8258/2 "2020-11-11T12:40:48Z")
@Ghan Confirm using telnet that you can indeed open a connection from arbitrator node to 10.10.10.201:4567. Since this is 8.0, SSL is enabled by default. Did you copy the SSL certificates from node1 to arbitrator node? If you already have a 3-node cluster, why are you adding a 4th member (arbitrator)? All this does is add the possibility of split-brain errors. Why do you feel you need the arbitrator? ---
**Author:** ![Cihan\_Tunali](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/cihan_tunali/32/4574_2.png) [@Cihan\_Tunali](https://forums.percona.com/u/Cihan_Tunali)\ **Post date:** [November 12, 2020, 1:31am UTC](https://forums.percona.com/t/adding-arbiter-to-existing-cluster/8258/3 "2020-11-12T01:31:42Z")
Hi @matthewb and thank you for your reply. First, I did not copy SSL certificates because it is not written at documentation page ([https://www.percona.com/doc/percona-xtradb-cluster/8.0/howtos/garbd\_howto.html](https://www.percona.com/doc/percona-xtradb-cluster/8.0/howtos/garbd_howto.html)) and i did not know it 🙂 Can you please guide me how to do that? Second, I will have 4 node cluster which will have 2 primary node, 1 arbiter and 1 primary with vote 0. The node which has vote 0, it will not become primary anymore but will keep up to date data so i will use this node to get storage snapshot (i will stop mysql service, get snapshot of disk by hardware level then start mysql service again). Thank you! ---
**Author:** ![matthewb](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/matthewb/32/34_2.png) [@matthewb](https://forums.percona.com/u/matthewb)\ **Post date:** [November 12, 2020, 12:41pm UTC](https://forums.percona.com/t/adding-arbiter-to-existing-cluster/8258/4 "2020-11-12T12:41:04Z")
You could change the weight of node1 to 2, node1 to 2, node3 to 0. That way, still a total vote of 3. If node3 goes offline, node1+node2 = 3. You are right, the SSL docs are not there. You need to SCP the .pem files from node1 over to arbitrator node and configure garb to use them. ---
**Author:** ![Cihan\_Tunali](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/cihan_tunali/32/4574_2.png) [@Cihan\_Tunali](https://forums.percona.com/u/Cihan_Tunali)\ **Post date:** [November 12, 2020, 1:32pm UTC](https://forums.percona.com/t/adding-arbiter-to-existing-cluster/8258/5 "2020-11-12T13:32:24Z")
I will change the weight of node1 to 1, node2 to 1, node3 to 0 and arbiter to 1. I think that will be enough. About SSL thing, after finding SSL files from node1, I dont know how to configure garb to use them ☹ ---
**Author:** ![matthewb](https://sea1.discourse-cdn.com/flex019/user_avatar/forums.percona.com/matthewb/32/34_2.png) [@matthewb](https://forums.percona.com/u/matthewb)\ **Post date:** [November 17, 2020, 10:04am UTC](https://forums.percona.com/t/adding-arbiter-to-existing-cluster/8258/6 "2020-11-17T10:04:43Z")
@Ghan You’ll need to read up on the galera arbitrator documentation for the parameters you need to pass to enable the SSL connectivity. There are some SSL examples here: [https://galeracluster.com/library/documentation/arbitrator.html](https://galeracluster.com/library/documentation/arbitrator.html)