NFS4 High Availability setup - Container integration¶
This howto describes a NFS4 Only HA service setup using modern OpenSVC features.
It has been tested on Red Hat Enterprise Linux 8.7 nodes.
Prerequisites¶
Prerequisite |
Example |
|---|---|
2 nodes |
node1
5.196.34.132node2
5.196.34.133 |
A failover ip address for NFS4 server |
nfsv4.opensvc.com |
Shared storage (san, iscsi, …) or drbd |
|
OpenSVC agent 2.1+ installed |
Setup LVM2¶
Configure a lvm2 volume group, to host a lvm2 logical volume to use as the drbd backing device
dnf -y install lvm2
pvcreate /dev/vdb
vgcreate datavg /dev/vdb
Setup DRBD¶
Kernel module & utils¶
Linbit DRBD kernel modules for RHEL are available on ElRepo
dnf -y install https://www.elrepo.org/elrepo-release-8.el8.elrepo.noarch.rpm
rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
sed -i 's/^mirrorlist/#mirrorlist/' /etc/yum.repos.d/elrepo.repo
dnf -y install kmod-drbd90 drbd90-utils
You can verify that drbd is ready with the command below
[root@node1 ~]# modinfo drbd | grep ^version version: 9.1.13
Setup podman¶
Install and configure podman for container management on Red Hat systems
dnf -y install podman
podman network create loopback
curl -o /etc/cni/net.d/loopback.conflist https://raw.githubusercontent.com/opensvc/opensvc_templates/main/nfs/loopback.conflist
mkdir -p /etc/containers/containers.conf.d
echo -e '[network]\ndefault_network = "loopback"' > /etc/containers/containers.conf.d/opensvc.loopback.conf
By default, cni connect a container on the podman network, and assign an ip addr in the 10.88.0.0/16 network.
As we expect that the network configuration is managed by the opensvc agent, we configure podman to connect containers on a basic private network namespace with only a loopback ip address
Setup OpenSVC¶
Install OpenSVC¶
On both nodes
dnf -y install python3 python3-cryptography
curl -o opensvc-2.1-latest.rpm https://repo.opensvc.com/rpms/2.1/current
dnf -y install ./opensvc-2.1-latest.rpm
Join cluster nodes¶
On node1
[root@node1 ~]# om cluster set --kw hb#1.type=unicast
[root@node1 ~]# om cluster set --kw cluster.name=cluster1
[root@node1 ~]# om cluster get --kw cluster.secret
b26a1e28b84a11edab28525400d67af6
On node2
[root@node2 ~]# om daemon join --node node1 --secret b26a1e28b84a11edab28525400d67af6
@ n:node2
local node is already frozen
join node node1
W local node is left frozen as it was already before join
On node1
Unfreeze nodes and setup root ssh trust:
om node thaw
om node update ssh authorized keys --node='*'
Note
Ensure that you can ssh as root from one node to another without being prompted for a password
You should now have a configured cluster, like:
[root@node1 ~]# om mon Threads node1 node2 daemon running | hb#1.rx running [::]:10000 | / O hb#1.tx running | / O listener running :1214 monitor running scheduler running Nodes node1 node2 score | 69 69 load 15m | 0.0 0.0 mem | 12/98%:1.77g 11/98%:1.77g swap | - - state | */svc/* node1 node2
Setup storage pool¶
We configure a cluster storage pool for volume objects automated provisioning. It is a drbd pool backed by a lvm2 volume group. More setups relying on other technologies are also supported.
On node1
om cluster set --kw pool#drbd.type=drbd --kw pool#drbd.vg=datavg --kw pool#drbd.status_schedule=@1
om pool status
[root@node1 ~]# om pool status name type caps head vols size used free |- default directory rox,rwx,roo,rwo,blk /var/lib/opensvc/pool/directory 0 9.89g 3.34g 6.55g `- shm shm rox,rwx,roo,rwo,blk /dev/shm 0 906m 84.0k 906m [root@node1 ~]# om cluster set --kw pool#drbd.type=drbd --kw pool#drbd.vg=datavg --kw pool#drbd.status_schedule=@1 [root@node1 ~]# om pool status name type caps head vols size used free |- default directory rox,rwx,roo,rwo,blk /var/lib/opensvc/pool/directory 0 9.89g 3.34g 6.55g |- drbd drbd rox,rwx,roo,rwo,snap,blk,shared datavg 1 100.0g 0m 100.0g `- shm shm rox,rwx,roo,rwo,blk /dev/shm 0 906m 84.0k 906m
Setup network configuration¶
We configure OpenSVC to share CNI configuration path with podman
om cluster set --kw cni.config="/etc/cni/net.d"
Deploy the service¶
Install config map¶
We create a config map object test/cfg/nfsv4 to store a exports key containing the /etc/exports file. The config map is replicated accross cluster nodes, and injected in the nfs container.
om test/cfg/nfsv4 create ;
curl -o - \
https://raw.githubusercontent.com/opensvc/opensvc_templates/main/nfs/etc.exports.conf | \
sed -e 's@ROOTFS@@' | \
om test/cfg/nfsv4 add --key exports --from=-
Note
The key export can be modified with the command om test/cfg/nfsv4 edit --key exports. The container is immediately updated with new content. Depending on applications, it may be needed to send signals or restart some process to reflect the change.
Deploy with NFS container disabled¶
Create the opensvc service using the name nfsv4, in the test namespace, using a 5G volume provisioned in the drbd pool, backed by datavg lvm2 volume group, reachable using the public dns name nfsv4.opensvc.com configured on interface named eth0 and default gateway 5.196.34.158
On node1
om test/svc/nfsv4 deploy \
--config https://raw.githubusercontent.com/opensvc/opensvc_templates/main/nfs/nfsv4-container-disabled.conf \
--env size=5G \
--env fqdn=nfsv4.opensvc.com \
--env gateway=5.196.34.158 \
--env nic=eth0
Note
The config used in this command has NFS container ressource disabled. Using that trick, we can configure NFS later, and test core (ip, disk, fs) failovers early.
This is convenient for tutoring, but in other situations you may want to use –config https://raw.githubusercontent.com/opensvc/opensvc_templates/main/nfs/nfsv4-container.conf for a one-step deployment.
This command creates and configures the system resources needed by the service on both nodes:
OpenSVC volume object
test/vol/nfsv4.test.svc.cluster15GB logical volume in datavg volume group
drbd ressources on both nodes (creation and synchronisation)
ext4 filesystem
OpenSVC service object
test/svc/nfsv4
After a few minutes (DRBD synchronisation time), you should end up in this situation:
Service object test/svc/nfsv4 status¶
[root@node1 ~]# om test/svc/nfsv4 print status -r test/svc/nfsv4 up `- instances |- node2 down idle `- node1 up idle, started |- ip#1 ........ up netns macvlan nfsv4.opensvc.com/27 eth0@container#0 |- volume#cfg ........ up nfsv4-cfg |- volume#data ........ up nfsv4-data |- container#0 ...../.. up podman ghcr.io/opensvc/pause |- container#debug ...O./.. up podman docker.io/opensvc/container_toolbox:latest |- container#nfs ..D../.. n/a podman docker.io/joebiellik/nfs4 |- sync#i0 ..DO./.. n/a rsync svc config to nodes `- task#export ...O./.. n/a task.host
Volume object test/vol/nfsv4-data status¶
[root@node1 ~]# om test/vol/nfsv4-data print status -r test/vol/nfsv4-data up |- instances | |- node2 stdby up idle | `- node1 up idle, started | |- disk#1 ......S. stdby up lv datavg/nfsv4-data.test.vol.cluster1 | |- disk#2 ......S. stdby up drbd nfsv4-data.test.vol.cluster1 | | info: Primary | |- fs#1 ........ up xfs /dev/drbd0@/srv/nfsv4-data.test.vol.cluster1 | `- sync#i0 ..DO./.. n/a rsync svc config to nodes `- children `- test/svc/nfsv4 up [root@node1 ~]#
Note
The agent automatically manages the dependency between the volume object and the service that uses it.
Test the core failover¶
This step is only useful to ensure ip, drbd and filesystem fails over forth and back between nodes, before continuing with the the NFS4 layer setup.
Initial situation¶
The green O means that the service is currently running on node1
On node1 or node2
[root@node1 ~]# om test/svc/nfsv4 mon test/svc/nfsv4 node1 node2 test/svc/nfsv4 up ha 1/1 | O^ S
Move service to node2¶
The switch action will relocate the service to the other node.
The red ^ means that the service is not running on its preferred node.
On node1 or node2
[root@node1 ~]# om test/svc/nfsv4 switch
@ n:node1 o:test/svc/nfsv4 sc:n
test/svc/nfsv4 defer target state set to placed@node2
[root@node1 ~]# om test/svc/nfsv4 mon
test/svc/nfsv4 node1 node2
test/svc/nfsv4 up^ ha 1/1 | S^ O
Move back service to node1¶
We can use either switch action, or giveback to move the service to its preferred node.
On node1 or node2
[root@node1 ~]# om test/svc/nfsv4 giveback
@ n:node1 o:test/svc/nfsv4 sc:n
test/svc/nfsv4 defer target state set to placed
[root@node1 ~]# om test/svc/nfsv4 mon
test/svc/nfsv4 node1 node2
test/svc/nfsv4 up ha 1/1 | O^ S
Enable NFS4¶
We only have to start the NFS container to open the service to nfs clients.
Enable & start NFS container resource¶
On node1
[root@node1 ~]# om test/svc/nfsv4 enable --rid container#nfs @ n:node1 o:test/svc/nfsv4 sc:n remove container#nfs.disable [root@node1 ~]# om test/svc/nfsv4 start --rid container#nfs @ n:node1 o:test/svc/nfsv4 sc:n add rid volume#cfg, volume#data to satisfy dependencies @ n:node1 o:test/vol/nfsv4-cfg r:fs#1 sc:n shmfs@/srv/nfsv4-cfg.test.vol.cluster1 is already mounted @ n:node1 o:test/vol/nfsv4-data r:disk#1 sc:n lv datavg/nfsv4-data.test.vol.cluster1 is already up @ n:node1 o:test/vol/nfsv4-data r:disk#2 sc:n drbd resource nfsv4-data.test.vol.cluster1 is already connected drbd resource nfsv4-data.test.vol.cluster1 is already Primary @ n:node1 o:test/vol/nfsv4-data r:fs#1 sc:n xfs /dev/drbd0@/srv/nfsv4-data.test.vol.cluster1 is already mounted @ n:node1 o:test/svc/nfsv4 r:container#nfs sc:n push start timeout to 05s (cached) + 02m (pull) /usr/bin/podman --cgroup-manager cgroupfs --namespace test/svc/nfsv4 --cni-config-dir /opt/cni/net.d run --detach --name=test..nfsv4.container.nfs --label=com.opensvc.id=2148c70b-6c1e-4b95-bb94-739d28e23507.container#nfs --label=com.opensvc.path=test/svc/nfsv4 --label=com.opensvc.namespace=test --label=com.opensvc.name=nfsv4 --label=com.opensvc.kind=svc --label=com.opensvc.rid=container#nfs --net=container:nfsv4.test.svc.cluster1 --privileged --interactive --tty --volume=/srv/nfsv4-data.test.vol.cluster1/nfsroot:/nfsroot:rw --volume=/srv/nfsv4-cfg.test.vol.cluster1/exports:/etc/exports:rw --cgroup-parent /opensvc.slice/test.slice/nfsv4.slice/container.slice/container.nfs.slice/libpod docker.io/joebiellik/nfs4 command successful but stderr: | Trying to pull docker.io/joebiellik/nfs4:latest... | Getting image source signatures | Copying blob sha256:9d73dea3c93cc738c79106e22047202fb44c2aedc67363efde3d800b9d0db133 | Copying blob sha256:a2256e557c9708413c79ce773b7836c1404f7854b23fcf98acb689f605b1d4f1 | Copying blob sha256:c9b1b535fdd91a9855fb7f82348177e5f019329a58c53c47272962dd60f71fc9 | Copying blob sha256:6d139d4da1b78cf4ee0252c4cf11a5cf1533c0cf335193994d7ba8adca3871af | Copying blob sha256:3b70709af63f2cddee828caa2b67ce6955d9970764c9fd1417b0f8897cea0158 | Copying blob sha256:629143a5f3af431ab94b4eb287ee0cb674398f5e8743190ee73578f671072893 | Copying blob sha256:f5fa07c1b71752a226cc735949df3b1de3809ffb9878ba7fd63aac12ddbed1c9 | Copying config sha256:cffcaf83b3f51ae506d98c18ae7409cc659a62d546321248d1f462f1a2fc9ba0 | Writing manifest to image destination | Storing signatures | e3ccb669cf66358dd7e37860bec0b0b29c131fd66f269ae451458342c982c9ba wait for up status wait for container operational [root@node1 ~]# om test/svc/nfsv4 print status -r test/svc/nfsv4 up `- instances |- node2 down idle `- node1 up idle, started |- ip#1 ........ up netns macvlan nfsv4.opensvc.com/27 eth0@container#0 |- volume#cfg ........ up nfsv4-cfg |- volume#data ........ up nfsv4-data |- container#0 ...../.. up podman ghcr.io/opensvc/pause |- container#debug ...O./.. up podman docker.io/opensvc/container_toolbox:latest |- container#nfs ...../.. up podman docker.io/joebiellik/nfs4 |- sync#i0 ..DO./.. n/a rsync svc config to nodes `- task#export ...O./.. n/a task.host [root@node1 ~]#
Test¶
Connect clients¶
You should be able to mount the nfsroot share from any client.
[root@client ~]# mount -v -t nfs4 -o proto=tcp,port=2049 nfsv4.opensvc.com:/ /mnt
mount.nfs4: timeout set for Thu Mar 2 17:11:37 2023
mount.nfs4: trying text-based options 'proto=tcp,port=2049,vers=4.2,addr=5.196.34.141,clientaddr=37.59.71.10'
[root@client ~]# df -h /mnt
Filesystem Size Used Avail Use% Mounted on
nfsv4.opensvc.com:/ 4860M 0 4560M 0% /mnt
Test the failover¶
Start nfs clients activity (fio runs for example).
Reboot the node hosting the active service instance.
Warning
Please note that OpenSVC is not responsible of the NFS4 container image joebiellik/nfs4. It may need adaptations to fit your requirements. You can also change it for another image.
Admin Tasks¶
modify exports¶
You may want to change the nfs exports list using the 2-steps procedure below
om test/cfg/nfsv4 edit --key exports
om test/svc/nfsv4 run --rid task#export
Note
The agent automatically push the new export file into the container once it is saved on disk. The task#export ressource execution proceed with the new nfs shares export.
network troubleshoot¶
If you experience any network issue, you can troubleshoot by entering the container network namespace using container#debug. It has all network tools (netstat, ip, …)
om test/svc/nfsv4 enter --rid container#debug