Snapshot fails for VM with running Docker container

Recently I noticed some Linux VM backups were failing and sometimes even crashing with following errors:
An error occurred while taking a snapshot: msg.snapshot.error-QUIESCINGERROR.
An error occurred while saving the snapshot: msg.snapshot.error-QUIESCINGERROR.

On closer look another error was visible in hostd.log file – Error when enabling the sync provider.

All of these VMs had one thing in common – they were running Docker containers.
I was not able to figure out why it happened but I was able to find a workaround – disable the VMWare Sync driver.

Copy-paste from Veritas KB article –

Steps to Disable VMware vmsync driver
To prevent the vmsync driver from being called during the quiesce phase of a VMware snapshot, edit the VMware Tools configuration file as follows:

1) Open a console session to the Redhat Linux virtual machine.
2) Navigate to the /etc/vmware-tools directory
3) Using a text editor, modify the tools.conf file with the following entry

enableSyncDriver = false

Note: If the tools.conf file does not exist, create a new empty file and add the above parameters.



ESXi will not resume syslog log sending when destination has been down for some time

Recently I was playing with ESXi syslog and Logstash + Graylog. For some reason Logstash instance died. After restarting the Logstash only some ESXi hosts resumed log sending. Quick google search revealed that it is a know issue and solution is to reload syslog on the host. After running following script in PowerCLI against my vCenter the log sending resumed.

$hosts = Get-VMHost
foreach($vihost in $hosts){
$esxcli = get-vmhost $vihost | Get-EsxCli

Good information about PowerCLI and ESXCLI: