Chapter 11. Operations on a Red Hat Gluster Storage Pod in an OpenShift Environment
This chapter lists out the various operations that can be performed on a Red Hat Gluster Storage pod (gluster pod):
- To list the pods, execute the following command :
# oc get pods
For example:# oc get pods NAME READY STATUS RESTARTS AGE storage-project-router-1-v89qc 1/1 Running 0 1d glusterfs-dc-node1.example.com 1/1 Running 0 1d glusterfs-dc-node2.example.com 1/1 Running 1 1d glusterfs-dc-node3.example.com 1/1 Running 0 1d heketi-1-k1u14 1/1 Running 0 23m rhel1 1/1 Running 0 26s
Following are the gluster pods from the above example:glusterfs-dc-node1.example.com glusterfs-dc-node2.example.com glusterfs-dc-node3.example.com
Note
The topology.json file will provide the details of the nodes in a given Trusted Storage Pool (TSP) . In the above example all the 3 Red Hat Gluster Storage nodes are from the same TSP. - To enter the gluster pod shell, execute the following command:
# oc rsh <gluster_pod_name>
For example:# oc rsh glusterfs-dc-node1.example.com sh-4.2#
- To get the peer status, execute the following command:
# gluster peer status
For example:# gluster peer status Number of Peers: 2 Hostname: node2.example.com Uuid: 9f3f84d2-ef8e-4d6e-aa2c-5e0370a99620 State: Peer in Cluster (Connected) Other names: node1.example.com Hostname: node3.example.com Uuid: 38621acd-eb76-4bd8-8162-9c2374affbbd State: Peer in Cluster (Connected)
- To list the gluster volumes on the Trusted Storage Pool, execute the following command:
# gluster volume info
For example:Volume Name: heketidbstorage Type: Distributed-Replicate Volume ID: 2fa53b28-121d-4842-9d2f-dce1b0458fda Status: Started Number of Bricks: 2 x 3 = 6 Transport-type: tcp Bricks: Brick1: 192.168.121.172:/var/lib/heketi/mounts/vg_1be433737b71419dc9b395e221255fb3/brick_c67fb97f74649d990c5743090e0c9176/brick Brick2: 192.168.121.233:/var/lib/heketi/mounts/vg_0013ee200cdefaeb6dfedd28e50fd261/brick_6ebf1ee62a8e9e7a0f88e4551d4b2386/brick Brick3: 192.168.121.168:/var/lib/heketi/mounts/vg_e4b32535c55c88f9190da7b7efd1fcab/brick_df5db97aa002d572a0fec6bcf2101aad/brick Brick4: 192.168.121.233:/var/lib/heketi/mounts/vg_0013ee200cdefaeb6dfedd28e50fd261/brick_acc82e56236df912e9a1948f594415a7/brick Brick5: 192.168.121.168:/var/lib/heketi/mounts/vg_e4b32535c55c88f9190da7b7efd1fcab/brick_65dceb1f749ec417533ddeae9535e8be/brick Brick6: 192.168.121.172:/var/lib/heketi/mounts/vg_7ad961dbd24e16d62cabe10fd8bf8909/brick_f258450fc6f025f99952a6edea203859/brick Options Reconfigured: performance.readdir-ahead: on Volume Name: vol_9e86c0493f6b1be648c9deee1dc226a6 Type: Distributed-Replicate Volume ID: 940177c3-d866-4e5e-9aa0-fc9be94fc0f4 Status: Started Number of Bricks: 2 x 3 = 6 Transport-type: tcp Bricks: Brick1: 192.168.121.168:/var/lib/heketi/mounts/vg_3fa141bf2d09d30b899f2f260c494376/brick_9fb4a5206bdd8ac70170d00f304f99a5/brick Brick2: 192.168.121.172:/var/lib/heketi/mounts/vg_7ad961dbd24e16d62cabe10fd8bf8909/brick_dae2422d518915241f74fd90b426a379/brick Brick3: 192.168.121.233:/var/lib/heketi/mounts/vg_5c6428c439eb6686c5e4cee56532bacf/brick_b3768ba8e80863724c9ec42446ea4812/brick Brick4: 192.168.121.172:/var/lib/heketi/mounts/vg_7ad961dbd24e16d62cabe10fd8bf8909/brick_0a13958525c6343c4a7951acec199da0/brick Brick5: 192.168.121.168:/var/lib/heketi/mounts/vg_17fbc98d84df86756e7826326fb33aa4/brick_af42af87ad87ab4f01e8ca153abbbee9/brick Brick6: 192.168.121.233:/var/lib/heketi/mounts/vg_5c6428c439eb6686c5e4cee56532bacf/brick_ef41e04ca648efaf04178e64d25dbdcb/brick Options Reconfigured: performance.readdir-ahead: on
- To get the volume status, execute the following command:
# gluster volume status <volname>
For example:# gluster volume status vol_9e86c0493f6b1be648c9deee1dc226a6 Status of volume: vol_9e86c0493f6b1be648c9deee1dc226a6 Gluster process TCP Port RDMA Port Online Pid ------------------------------------------------------------------------------ Brick 192.168.121.168:/var/lib/heketi/mounts/v g_3fa141bf2d09d30b899f2f260c494376/brick_9f b4a5206bdd8ac70170d00f304f99a5/brick 49154 0 Y 3462 Brick 192.168.121.172:/var/lib/heketi/mounts/v g_7ad961dbd24e16d62cabe10fd8bf8909/brick_da e2422d518915241f74fd90b426a379/brick 49154 0 Y 115939 Brick 192.168.121.233:/var/lib/heketi/mounts/v g_5c6428c439eb6686c5e4cee56532bacf/brick_b3 768ba8e80863724c9ec42446ea4812/brick 49154 0 Y 116134 Brick 192.168.121.172:/var/lib/heketi/mounts/v g_7ad961dbd24e16d62cabe10fd8bf8909/brick_0a 13958525c6343c4a7951acec199da0/brick 49155 0 Y 115958 Brick 192.168.121.168:/var/lib/heketi/mounts/v g_17fbc98d84df86756e7826326fb33aa4/brick_af 42af87ad87ab4f01e8ca153abbbee9/brick 49155 0 Y 3481 Brick 192.168.121.233:/var/lib/heketi/mounts/v g_5c6428c439eb6686c5e4cee56532bacf/brick_ef 41e04ca648efaf04178e64d25dbdcb/brick 49155 0 Y 116153 NFS Server on localhost 2049 0 Y 116173 Self-heal Daemon on localhost N/A N/A Y 116181 NFS Server on node1.example.com 2049 0 Y 3501 Self-heal Daemon on node1.example.com N/A N/A Y 3509 NFS Server on 192.168.121.172 2049 0 Y 115978 Self-heal Daemon on 192.168.121.172 N/A N/A Y 115986 Task Status of Volume vol_9e86c0493f6b1be648c9deee1dc226a6 ------------------------------------------------------------------------------ There are no active volume tasks
- To use the snapshot feature, load the snapshot module using the following command:
# - modprobe dm_snapshot
Important
Restrictions for using Snapshot- After a snapshot is created, it must be accessed though the user-serviceable snapshots feature only. This can be used to copy the old versions of files into the required location.Reverting the volume to a snapshot state is not supported and should never be done as it might damage the consistency of the data.
- On a volume with snapshots, volume changing operations, such as volume expansion, must not be performed.
- To take the snapshot of the gluster volume, execute the following command:
# gluster snapshot create <snapname> <volname>
For example:# gluster snapshot create snap1 vol_9e86c0493f6b1be648c9deee1dc226a6 snapshot create: success: Snap snap1_GMT-2016.07.29-13.05.46 created successfully
- To list the snapshots, execute the following command:
# gluster snapshot list
For example:# gluster snapshot list snap1_GMT-2016.07.29-13.05.46 snap2_GMT-2016.07.29-13.06.13 snap3_GMT-2016.07.29-13.06.18 snap4_GMT-2016.07.29-13.06.22 snap5_GMT-2016.07.29-13.06.26
- To delete a snapshot, execute the following command:
# gluster snap delete <snapname>
For example:# gluster snap delete snap1_GMT-2016.07.29-13.05.46 Deleting snap will erase all the information about the snap. Do you still want to continue? (y/n) y snapshot delete: snap1_GMT-2016.07.29-13.05.46: snap removed successfully
For more information about managing snapshots, refer https://access.redhat.com/documentation/en-us/red_hat_gluster_storage/3.2/html-single/administration_guide/#chap-Managing_Snapshots. - You can set up Container-Native Storage volumes for geo-replication to a non-Container-Native Storage remote site. Geo-replication uses a master–slave model. Here, the Container-Native Storage volume acts as the master volume. To set up geo-replication, you must run the geo-replication commands on gluster pods. To enter the gluster pod shell, execute the following command:
# oc rsh <gluster_pod_name>
For more information about setting up geo-replication, refer https://access.redhat.com/documentation/en-us/red_hat_gluster_storage/3.2/html/administration_guide/chap-managing_geo-replication. - Brick multiplexing is a feature that allows including multiple bricks into one process. This reduces resource consumption, allowing you to run more bricks than earlier with the same memory consumption.Brick multiplexing is enabled by default from Container-Native Storage 3.6. If you want to turn it off, execute the following command:
# gluster volume set all cluster.brick-multiplex off
- The
auto_unmountoption in glusterfs libfuse, when enabled, ensures that the file system is unmounted at FUSE server termination by running a separate monitor process that performs the unmount.The GlusterFS plugin in Openshift enables theauto_unmountoption for gluster mounts.
