[ClusterLabs] Antw: [EXT] Re: VirtualDomain & "deeper" monitors - what/how?
Kyle O'Donnell
kyleo at 0b10.mx
Mon Oct 25 15:34:28 EDT 2021
Finally got around to working on this.
I spoke with someone on the #cluterslabs IRC channel who mentioned that the monitor_scripts param does indeed run at some frequency (op monitor timeout=? interval=?), not just during the "start" and "migrate_from" actions.
The monitor_scripts param does not support scripts with command line args, just a space delimited list for running multiple scripts. This means that each VirtualDomain resource needs its own script to be able to define the ${DOMAIN_NAME}. I found that a bit annoying so I created a symlink to a wrapper script using the ${DOMAIN_NAME} as the first part of the filename and a separator for awk:
ln -s /path/to/wrapper_script.sh /path/to/wrapper/myvmhostname_____wrapper_script.sh
and in my wrapper_script.sh:
#!/bin/bash
DOMAIN_NAME=$(basename "$0" |awk -F'____' '{print $1}')
/path/to/myscript.sh -H ${DOMAIN_NAME} -C guest-get-time -l 25 -w 1
(a bit hack-y but better than creating 1 script per vm resource and modifying it with the ${DOMAIN_NAME})
Then creating the cluster resource:
pcs resource create myvmhostname VirtualDomain config="/path/to/myvmhostname/myvmhostname.xml" hypervisor="qemu:///system" migration_transport="ssh" force_stop="false" monitor_scripts="/path/to/wrapper/myvmhostname_____wrapper_script.sh" meta allow-migrate="true" target-role="Stopped" op migrate_from timeout=90s interval=0s op migrate_to timeout=120s interval=0s op monitor timeout=40s interval=10s op start timeout=90s interval=0s op stop timeout=90s interval=0s
‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Sunday, June 6th, 2021 at 16:56, Kyle O'Donnell <kyleo at 0b10.mx> wrote:
> Let me know if there is a better approach to the following problem. When the virtual machine does not respond to a state query I want the cluster to kick it
>
> I could not find any useful docs for using the nagios plugins. After reading the documentation about running a custom script via the "monitor" function in the RA I determined that would not meet my requirements as it's only run on start and migrate(unless I read it incorrectly?).
>
> Here is what I did (im on ubuntu 20.04):
>
> cp /usr/lib/ocf/resource.d/heartbeat/VirtualDomain /usr/lib/ocf/resource.d/heartbeat/MyVirtDomain
>
> cp /usr/share/resource-agents/ocft/configs/VirtualDomain cp /usr/share/resource-agents/ocft/configs/MyVirtDomain
>
> sed -i 's/VirtualDomain/MyVirtDomain/g' /usr/lib/ocf/resource.d/heartbeat/MyVirtDomain
>
> sed -i 's/VirtualDomain/MyVirtDomain/g' /usr/share/resource-agents/ocft/configs/MyVirtDomain
>
> edited function MyVirtDomain_status in /usr/lib/ocf/resource.d/heartbeat/MyVirtDomain, adding the following to the status case running|paused|idle|blocked|"in shutdown")
>
> FROM
>
> running|paused|idle|blocked|"in shutdown")
>
> # running: domain is currently actively consuming cycles
>
> # paused: domain is paused (suspended)
>
> # idle: domain is running but idle
>
> # blocked: synonym for idle used by legacy Xen versions
>
> # in shutdown: the domain is in process of shutting down, but has not completely shutdown or crashed.
>
> ocf_log debug "Virtual domain $DOMAIN_NAME is currently $status."
>
> rc=$OCF_SUCCESS
>
> TO
>
> running|paused|idle|blocked|"in shutdown")
>
> # running: domain is currently actively consuming cycles
>
> # paused: domain is paused (suspended)
>
> # idle: domain is running but idle
>
> # blocked: synonym for idle used by legacy Xen versions
>
> # in shutdown: the domain is in process of shutting down, but has not completely shutdown or crashed.
>
> custom_chk=$(/path/to/myscript.sh -H $DOMAIN_NAME -C guest-get-time -l 25 -w 1)
>
> custom_rc=$?
>
> if [ ${custom_rc} -eq 0 ]; then
>
> ocf_log debug "Virtual domain $DOMAIN_NAME is currently $status."
>
> rc=$OCF_SUCCESS
>
> else
>
> ocf_log debug "Virtual domain $DOMAIN_NAME is currently ${custom_chk}."
>
> rc=$OCF_ERR_GENERIC
>
> fi
>
> The custom script uses the qemu-guest-agent in my guest, passing the parameter to grab the guest's time (seems to be most universal [windows, centos6, ubuntu, centos 7]). Runs 25 loops, sleeps 1 second between iterations, exit 0 as soon as the agent responds with the time and exit 1 after the 25th loop, which are OCF_SUCCESS and OCF_ERR_GENERIC based on docs.
>
> /path/to/myscript.sh -H myvm -C guest-get-time -l 25 -w 1
> =========================================================
>
> [GOOD] - myvm virsh qemu-agent-command guest-get-time output: {"return":1623011582178375000}
>
> or when its not responding:
>
> /path/to/myscript.sh -H myvm -C guest-get-time -l 25 -w 1
> =========================================================
>
> [BAD] - myvm virsh qemu-agent-command guest-get-time output: error: Guest agent is not responding: QEMU guest agent is not connected
>
> [BAD] - myvm virsh qemu-agent-command guest-get-time output: error: Guest agent is not responding: QEMU guest agent is not connected
>
> [BAD] - myvm virsh qemu-agent-command guest-get-time output: error: Guest agent is not responding: QEMU guest agent is not connected
>
> [BAD] - myvm virsh qemu-agent-command guest-get-time output: error: Guest agent is not responding: QEMU guest agent is not connected
>
> ... (exits after 25th or
>
> [GOOD] - myvm virsh qemu-agent-command guest-get-time output: {"return":1623011582178375000}
>
> and when the vm isnt running:
>
> /path/to/myscript.sh -H myvm -C guest-get-time -l 25 -w 1
> =========================================================
>
> [BAD] - myvm virsh qemu-agent-command guest-get-time output: error: failed to get domain 'myvm'
>
> I updated my test vm to use the new RA, updated the status timeout to 40s from default of 30s just in case.
>
> I'd like to be able to update the parameters to myscript.sh via crm configure edit at some point, but will figure that out later...
>
> My test:
>
> reboot the VM from within the OS, hit escape so that I enter the boot mode prompt... after ~30 seconds the cluster decides the resource is having a problem, marks it as failed, and restarts the virtual machine (on the same node -- which in my case in desirable), once the guest is back up and responding the cluster reports the VM as Started
>
> I still have plenty more testing to do and will keep the list posted on progress.
>
> -Kyle
>
> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>
> On Thursday, May 27th, 2021 at 05:34, Kyle O'Donnell kyleo at 0b10.mx wrote:
>
> > guest-get-fsinfo doesn't seem to work on older agents (centos6) I've found guest-get-time more universal.
> >
> > Also, found this helpful thread on using monitor_scripts which is part of the VirtualDomain RA
> >
> > https://linux-ha-dev.linux-ha.narkive.com/yxvySDA2/monitor-scripts-parameter-for-the-virtualdomain-ra-was-re-linux-ha-ocf-resource-agent-for-kvm
> >
> > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> >
> > On Sunday, May 16th, 2021 at 22:49, Kyle O'Donnell kyleo at 0b10.mx wrote:
> >
> > > I am thinking about using the qemu-guest-agent to run one of the available commands to determine the health of the OS inside
> > >
> > > virsh qemu-agent-command myvm --pretty '{"execute":"guest-get-fsinfo"}'
> > >
> > > https://qemu-project.gitlab.io/qemu/interop/qemu-ga-ref.html
> > >
> > > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> > >
> > > On Thursday, May 13th, 2021 at 01:28, Andrei Borzenkov arvidjaar at gmail.com wrote:
> > >
> > > > On 03.05.2021 09:48, Ulrich Windl wrote:
> > > >
> > > > > > > > Ken Gaillot kgaillot at redhat.com schrieb am 30.04.2021 um 16:57 in
> > > > > > > >
> > > > > > > > Nachricht
> > > > > > > >
> > > > > > > > 3acef4bc31923fb019619c713300444c2dcd354a.camel at redhat.com:
> > > > > > > >
> > > > > > > > On Fri, 2021‑04‑30 at 11:00 +0100, lejeczek wrote:
> > > > > >
> > > > > > > Hi guys
> > > > > > >
> > > > > > > I'd like to ask around for thoughts & suggestions on any
> > > > > > >
> > > > > > > semi/official ways to monitor VirtualDomain.
> > > > > > >
> > > > > > > Something beyond what included RA does ‑ such as actual
> > > > > > >
> > > > > > > health testing of and communication with VM's OS.
> > > > > > >
> > > > > > > many thanks, L.
> > > > > >
> > > > > > This use case led to a Pacemaker feature many moons ago ...
> > > > > >
> > > > > > Pacemaker supports nagios plug‑ins as a resource type (e.g.
> > > > > >
> > > > > > nagios:check_apache_status). These are service checks usually used with
> > > > > >
> > > > > > monitoring software such as nagios, icinga, etc.
> > > > > >
> > > > > > If the service being monitored is inside a VirtualDomain, named vm1 for
> > > > > >
> > > > > > example, you can configure the nagios resource with the resource meta‑
> > > > > >
> > > > > > attribute container="vm1". If the nagios check fails, Pacemaker will
> > > > > >
> > > > > > restart vm1.
> > > > >
> > > > > "check fails" mans WARNING, CRITICAL, or UNKNOWN? ;-)
> > > >
> > > > switch (rc) {
> > > >
> > > > case NAGIOS_STATE_OK:
> > > >
> > > > return PCMK_OCF_OK;
> > > >
> > > > case NAGIOS_INSUFFICIENT_PRIV:
> > > >
> > > > return PCMK_OCF_INSUFFICIENT_PRIV;
> > > >
> > > > case NAGIOS_NOT_INSTALLED:
> > > >
> > > > return PCMK_OCF_NOT_INSTALLED;
> > > >
> > > > case NAGIOS_STATE_WARNING:
> > > >
> > > > case NAGIOS_STATE_CRITICAL:
> > > >
> > > > case NAGIOS_STATE_UNKNOWN:
> > > >
> > > > case NAGIOS_STATE_DEPENDENT:
> > > >
> > > > default:
> > > >
> > > > return PCMK_OCF_UNKNOWN_ERROR;
> > > >
> > > > }
> > > >
> > > > return PCMK_OCF_UNKNOWN_ERROR;
> > > >
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> > > >
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>
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