We've got an odd problem where clients are blocked from writing to Gluster volumes until the first node of the Gluster cluster is rebooted.

I suspect I've either configured something incorrectly with the arbiter / replica configuration of the volumes, or there is some sort of bug in the gluster client-server connection that we're triggering.

I was wondering if anyone has seen this or could point me in the right direction?

Environment:

• Typology: 3 node cluster, replica 2, arbiter 1 (third node is metadata only).
  
• Version: Client and Servers both running 4.1.3, both on CentOS 7, kernel 4.18.x, (Xen) VMs with relatively fast networked SSD storage backing them, XFS.
  
• Client: Native Gluster FUSE client mounting via the kubernetes provider
  

Problem:

• Seemingly randomly some clients will be blocked / are unable to write to what should be a highly available gluster volume.
  
• The client gluster logs show it failing to do new file operations across various volumes and all three nodes of the gluster.
  
• The server gluster (or OS) logs do not show any warnings or errors.
  
• The client recovers and is able to write to volumes again after the first node of the gluster cluster is rebooted.
  
• Until the first node of the gluster cluster is rebooted, the client fails to write to the volume that is (or should be) available on the second node (a replica) and third node (an arbiter only node).
  

What 'fixes' the issue:

• Although the clients (kubernetes hosts) connect to all 3 nodes of the Gluster cluster - restarting the first gluster node always unblocks the IO and allows the client to continue writing.
  
• Stopping and starting the glusterd service on the gluster server is not enough to fix the issue, nor is restarting its networking.
  
• This suggests to me that the volume is unavailable for writing for some reason and restarting the first node in the cluster either clears some sort of TCP sessions between the client-server or between the server-server replication.
  

Expected behaviour:

• If the first gluster node / server had failed or was blocked from performing operations for some reason (which it doesn't seem it is), I'd expect the clients to access data from the second gluster node and write metadata to the third gluster node as well as it's an arbiter / metadata only node.
  
• If for some reason the a gluster node was not able to serve connections to clients, I'd expect to see errors in the volume, glusterd or brick log files (there are none on the first gluster node).
  
• If the first gluster node was for some reason blocking IO on a volume, I'd expect that node either to show as unhealthy or unavailable in the gluster peer status or gluster volume status.
  

Client gluster errors:

• staging_static in this example is a volume name.
  
• You can see the client trying to connect to the second and third nodes of the gluster cluster and failing (unsure as to why?)
  
• The server side logs on the first gluster node do not show any errors or problems, but the second / third node show errors in the glusterd.log when trying to 'unlock' the 0-management volume on the first node.
  

On a gluster client (a kubernetes host using the kubernetes connector which uses the native fuse client) when its blocked from writing but the gluster appears healthy (other than the errors mentioned later):

[2018-09-02 15:33:22.750874] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-2: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x1cce sent = 2018-09-02 15:03:22.417773. timeout = 1800 for <ip of third gluster node>:49154

[2018-09-02 15:33:22.750989] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-2: remote operation failed [Transport endpoint is not connected]

[2018-09-02 16:03:23.097905] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-1: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x2e21 sent = 2018-09-02 15:33:22.765751. timeout = 1800 for <ip of second gluster node>:49154

[2018-09-02 16:03:23.097988] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-1: remote operation failed [Transport endpoint is not connected]

[2018-09-02 16:33:23.439172] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-2: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x1d4b sent = 2018-09-02 16:03:23.098133. timeout = 1800 for <ip of third gluster node>:49154

[2018-09-02 16:33:23.439282] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-2: remote operation failed [Transport endpoint is not connected]

[2018-09-02 17:03:23.786858] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-1: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x2ee7 sent = 2018-09-02 16:33:23.455171. timeout = 1800 for <ip of second gluster node>:49154

[2018-09-02 17:03:23.786971] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-1: remote operation failed [Transport endpoint is not connected]

[2018-09-02 17:33:24.160607] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-2: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x1dc8 sent = 2018-09-02 17:03:23.787120. timeout = 1800 for <ip of third gluster node>:49154

[2018-09-02 17:33:24.160720] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-2: remote operation failed [Transport endpoint is not connected]

[2018-09-02 18:03:24.505092] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-1: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x2faf sent = 2018-09-02 17:33:24.173153. timeout = 1800 for <ip of second gluster node>:49154

[2018-09-02 18:03:24.505185] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-1: remote operation failed [Transport endpoint is not connected]

[2018-09-02 18:33:24.841248] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-2: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x1e45 sent = 2018-09-02 18:03:24.505328. timeout = 1800 for <ip of third gluster node>:49154

[2018-09-02 18:33:24.841311] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-2: remote operation failed [Transport endpoint is not connected]

[2018-09-02 19:03:25.204711] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-1: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x3074 sent = 2018-09-02 18:33:24.855372. timeout = 1800 for <ip of second gluster node>:49154

[2018-09-02 19:03:25.204784] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-1: remote operation failed [Transport endpoint is not connected]

[2018-09-02 19:33:25.533545] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-2: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x1ec2 sent = 2018-09-02 19:03:25.204977. timeout = 1800 for <ip of third gluster node>:49154

[2018-09-02 19:33:25.533611] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-2: remote operation failed [Transport endpoint is not connected]

[2018-09-02 20:03:25.877020] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-1: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x3138 sent = 2018-09-02 19:33:25.545921. timeout = 1800 for <ip of second gluster node>:49154

[2018-09-02 20:03:25.877098] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-1: remote operation failed [Transport endpoint is not connected]

[2018-09-02 20:33:26.217858] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-2: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x1f3e sent = 2018-09-02 20:03:25.877264. timeout = 1800 for <ip of third gluster node>:49154

[2018-09-02 20:33:26.217973] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-2: remote operation failed [Transport endpoint is not connected]

[2018-09-02 21:03:26.588237] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-1: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x31ff sent = 2018-09-02 20:33:26.233010. timeout = 1800 for <ip of second gluster node>:49154

[2018-09-02 21:03:26.588316] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-1: remote operation failed [Transport endpoint is not connected]

[2018-09-02 21:33:26.912334] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-2: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x1fbb sent = 2018-09-02 21:03:26.588456. timeout = 1800 for <ip of third gluster node>:49154

[2018-09-02 21:33:26.912449] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-2: remote operation failed [Transport endpoint is not connected]

[2018-09-02 22:03:37.258915] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-1: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x32c5 sent = 2018-09-02 21:33:32.091009. timeout = 1800 for <ip of second gluster node>:49154

[2018-09-02 22:03:37.259000] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-1: remote operation failed [Transport endpoint is not connected]

[2018-09-02 22:33:37.615497] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-2: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x2039 sent = 2018-09-02 22:03:37.259147. timeout = 1800 for <ip of third gluster node>:49154

[2018-09-02 22:33:37.615574] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-2: remote operation failed [Transport endpoint is not connected]

[2018-09-02 23:03:37.940969] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-1: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x3386 sent = 2018-09-02 22:33:37.629655. timeout = 1800 for <ip of second gluster node>:49154

[2018-09-02 23:03:37.941049] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-1: remote operation failed [Transport endpoint is not connected]

[2018-09-02 23:33:38.270998] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-2: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x20b5 sent = 2018-09-02 23:03:37.941199. timeout = 1800 for <ip of third gluster node>:49154

[2018-09-02 23:33:38.271078] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-2: remote operation failed [Transport endpoint is not connected]

[2018-09-03 00:03:38.607186] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-1: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x3447 sent = 2018-09-02 23:33:38.285899. timeout = 1800 for <ip of second gluster node>:49154

[2018-09-03 00:03:38.607263] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-1: remote operation failed [Transport endpoint is not connected]

[2018-09-03 00:33:38.934385] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-2: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x2131 sent = 2018-09-03 00:03:38.607410. timeout = 1800 for <ip of third gluster node>:49154

[2018-09-03 00:33:38.934479] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-2: remote operation failed [Transport endpoint is not connected]

[2018-09-03 01:03:39.256842] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-1: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x350c sent = 2018-09-03 00:33:38.948570. timeout = 1800 for <ip of second gluster node>:49154

[2018-09-03 01:03:39.256972] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-1: remote operation failed [Transport endpoint is not connected]

[2018-09-03 01:33:39.614402] E [rpc-clnt.c:184:call_bail] 0-staging_static-client-2: bailing out frame type(GlusterFS 4.x v1) op(INODELK(29)) xid = 0x21ae sent = 2018-09-03 01:03:39.258166. timeout = 1800 for <ip of third gluster node>:49154

[2018-09-03 01:33:39.614483] E [MSGID: 114031] [client-rpc-fops_v2.c:1306:client4_0_inodelk_cbk] 0-staging_static-client-2: remote operation failed [Transport endpoint is not connected]

On the second gluster server:

We are seeing the following error in the glusterd.log file when the client is blocked from writing the volume, I think this is probably the most important information about the error and suggests a problem with the first node but doesn't explain the client behaviour:

[2018-09-02 08:31:03.902272] E [MSGID: 106115] [glusterd-mgmt.c:124:gd_mgmt_v3_collate_errors] 0-management: Unlocking failed on <FQDN of the first gluster node>. Please check log file for details.

[2018-09-02 08:31:03.902477] E [MSGID: 106151] [glusterd-syncop.c:1640:gd_unlock_op_phase] 0-management: Failed to unlock on some peer(s)

Note in the above error:

1. I'm not sure which log to check (there doesn't seem to be a management brick / brick log)?

2. If there's a problem with the first node, why isn't it rejected from the gluster / taken offline / the health of the peers or volume list degraded?

3. Why does the client fail to write to the volume rather than (I'm assuming) trying the second (or third I guess) node to write to the volume?

We are also seeing the following errors repeated a lot in the logs, both when the volumes are working and when there's an issue in the brick log (/var/log/glusterfs/bricks/mnt-gluster-storage-staging_static.log):

[2018-09-03 01:58:35.128923] E [server.c:137:server_submit_reply] (-->/usr/lib64/glusterfs/4.1.2/xlator/debug/io-stats.so(+0x1fd14) [0x7f8470319d14] -->/usr/lib64/glusterfs/4.1.2/xlator/protocol/server.so(+0x5f24a) [0x7f846bdde24a] -->/usr/lib64/glusterfs/4.1.2/xlator/protocol/server.so(+0xafce) [0x7f846bd89fce] ) 0-: Reply submission failed

[2018-09-03 01:58:35.128957] E [rpcsvc.c:1378:rpcsvc_submit_generic] 0-rpc-service: failed to submit message (XID: 0x3d60, Program: GlusterFS 4.x v1, ProgVers: 400, Proc: 29) to rpc-transport (tcp.staging_static-server)

[2018-09-03 01:58:35.128983] E [server.c:137:server_submit_reply] (-->/usr/lib64/glusterfs/4.1.2/xlator/debug/io-stats.so(+0x1fd14) [0x7f8470319d14] -->/usr/lib64/glusterfs/4.1.2/xlator/protocol/server.so(+0x5f24a) [0x7f846bdde24a] -->/usr/lib64/glusterfs/4.1.2/xlator/protocol/server.so(+0xafce) [0x7f846bd89fce] ) 0-: Reply submission failed

[2018-09-03 01:58:35.129016] E [rpcsvc.c:1378:rpcsvc_submit_generic] 0-rpc-service: failed to submit message (XID: 0x3e2a, Program: GlusterFS 4.x v1, ProgVers: 400, Proc: 29) to rpc-transport (tcp.staging_static-server)

[2018-09-03 01:58:35.129042] E [server.c:137:server_submit_reply] (-->/usr/lib64/glusterfs/4.1.2/xlator/debug/io-stats.so(+0x1fd14) [0x7f8470319d14] -->/usr/lib64/glusterfs/4.1.2/xlator/protocol/server.so(+0x5f24a) [0x7f846bdde24a] -->/usr/lib64/glusterfs/4.1.2/xlator/protocol/server.so(+0xafce) [0x7f846bd89fce] ) 0-: Reply submission failed

[2018-09-03 01:58:35.129077] E [rpcsvc.c:1378:rpcsvc_submit_generic] 0-rpc-service: failed to submit message (XID: 0x3ef6, Program: GlusterFS 4.x v1, ProgVers: 400, Proc: 29) to rpc-transport (tcp.staging_static-server)

[2018-09-03 01:58:35.129149] E [server.c:137:server_submit_reply] (-->/usr/lib64/glusterfs/4.1.2/xlator/debug/io-stats.so(+0x1fd14) [0x7f8470319d14] -->/usr/lib64/glusterfs/4.1.2/xlator/protocol/server.so(+0x5f24a) [0x7f846bdde24a] -->/usr/lib64/glusterfs/4.1.2/xlator/protocol/server.so(+0xafce) [0x7f846bd89fce] ) 0-: Reply submission failed

[2018-09-03 01:58:35.129191] E [rpcsvc.c:1378:rpcsvc_submit_generic] 0-rpc-service: failed to submit message (XID: 0x3fc6, Program: GlusterFS 4.x v1, ProgVers: 400, Proc: 29) to rpc-transport (tcp.staging_static-server)

[2018-09-03 01:58:35.129219] E [server.c:137:server_submit_reply] (-->/usr/lib64/glusterfs/4.1.2/xlator/debug/io-stats.so(+0x1fd14) [0x7f8470319d14] -->/usr/lib64/glusterfs/4.1.2/xlator/protocol/server.so(+0x5f24a) [0x7f846bdde24a] -->/usr/lib64/glusterfs/4.1.2/xlator/protocol/server.so(+0xafce) [0x7f846bd89fce] ) 0-: Reply submission failed

Gluster volume information:

# gluster volume info staging_static

Volume Name: staging_static

Type: Replicate

Volume ID: 7f3b8e91-afea-4fc6-be83-3399a089b6f3

Status: Started

Snapshot Count: 0

Number of Bricks: 1 x (2 + 1) = 3

Transport-type: tcp

Bricks:

Brick1: <first gluster node.fqdn>:/mnt/gluster-storage/staging_static

Brick2: <second gluster node.fqdn>:/mnt/gluster-storage/staging_static

Brick3: <third gluster node.fqdn>:/mnt/gluster-storage/staging_static (arbiter)

Options Reconfigured:

storage.fips-mode-rchecksum: true

cluster.self-heal-window-size: 16

cluster.shd-wait-qlength: 4096

cluster.shd-max-threads: 8

performance.cache-min-file-size: 2KB

performance.rda-cache-limit: 1GB

network.inode-lru-limit: 50000

server.outstanding-rpc-limit: 256

transport.listen-backlog: 2048

performance.write-behind-window-size: 512MB

performance.stat-prefetch: true

performance.io-thread-count: 16

performance.client-io-threads: true

performance.cache-size: 1GB

performance.cache-refresh-timeout: 60

performance.cache-invalidation: true

cluster.use-compound-fops: true

cluster.readdir-optimize: true

cluster.lookup-optimize: true

cluster.favorite-child-policy: size

cluster.eager-lock: true

client.event-threads: 4

nfs.disable: on

transport.address-family: inet

diagnostics.brick-log-level: ERROR

diagnostics.client-log-level: ERROR

features.cache-invalidation-timeout: 300

features.cache-invalidation: true

network.ping-timeout: 15

performance.cache-max-file-size: 3MB

performance.md-cache-timeout: 300

server.event-threads: 4

Thanks in advance,

--
Sam McLeod (protoporpoise on IRC)

https://smcleod.net
https://twitter.com/s_mcleod

Words are my own opinions and do not necessarily represent those of my employer or partners.