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Problem report
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Resolution: Fixed
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Trivial
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5.0.25, 5.0.26, 6.0.6, 6.0.7, 6.2.0, 6.2.1
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Sprint 92 (Sep 2022)
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0.5
With zabbix-agent2 running on virtual machines sometimes we get unsupported items for file system monitoring.
In such cases random file systems on random hosts become unavailable with following error message:
ZBX_NOTSUPPORTED: 'mount '***' is unavailable' to '***'
Debug logs says something like that:
Aug 11 11:59:13 zabbix_agent2[14758]: received passive check request: 'vfs.fs.size[/opt,total]' from '10.9.49.35' Aug 11 11:59:13 zabbix_agent2[14758]: [1] processing update request (1 requests) Aug 11 11:59:13 zabbix_agent2[14758]: [1] adding new request for key: 'vfs.fs.size[/opt,total]' Aug 11 11:59:13 zabbix_agent2[14758]: [1] created direct exporter task for plugin 'VfsFs' itemid:0 key 'vfs.fs.size[/opt,total]' Aug 11 11:59:13 zabbix_agent2[14758]: executing direct exporter task for key 'vfs.fs.size[/opt,total]' Aug 11 11:59:13 zabbix_agent2[14758]: failed to execute direct exporter task for key 'vfs.fs.size[/opt,total]' error: 'mount '/opt' is unavailable' Aug 11 11:59:13 zabbix_agent2[14758]: sending passive check response: ZBX_NOTSUPPORTED: 'mount '/opt' is unavailable' to '10.9.49.35'
Such behavior starts with log message.
$ sudo journalctl -u zabbix-agent2 --since '3 days ago' | grep 'timed out' Aug 08 15:33:26 nl-build17.local.profee.com zabbix_agent2[14758]: check 'vfs.fs.size[/opt,free]' is not supported: operation on mount '/opt' timed out
After that file system never become available. Helps only restart of zabbix-agent2 service.
We looked thru the source code of `VfsFs` module. It seems like this branch of code that makes file system available never will be executed.
https://github.com/zabbix/zabbix/blob/master/src/go/plugins/vfs/fs/fscaller.go#L64-L70
func (f *fsCaller) execute(path string) { stats, err := f.fsFunc(path) if isStuck(path) { f.p.Debugf("mount '%s' has become available", path) stuckMux.Lock() stuckMounts[path] = false stuckMux.Unlock() return } # ...
Only one call of the 'execute' happens inside of 'run' function.
https://github.com/zabbix/zabbix/blob/master/src/go/plugins/vfs/fs/fscaller.go#L41-L46
func (f *fsCaller) run(path string) (stat *FsStats, err error) { if isStuck(path) { return nil, fmt.Errorf("mount '%s' is unavailable", path) } go f.execute(path) # ...
This pieces of code looks vary strange. In both cases it checks the same condition. But in one case file system become available, in another remains unavailable.
