Common update error recovery procedures

This section describes common error messages during updates, and provides procedures for recovering and continuing.

A snapshot with the given tag already exists

When an update attempt fails, the update script does not remove the snapshot it creates at the beginning of the update process. Use this procedure to remove the tag of the pre-update snapshot and restart the update. Untagged snapshots are removed when their time-to-live (TTL) expires. The TTL value is defined by the SERVICED_SNAPSHOT_TTL variable in the Control Center configuration file.

Log in to the Control Center master host as a user with serviced CLI privileges.

Create a variable for the identifier of the tenant application.

myTenant=$(serviced service list Zenoss.resmgr --format='{{.ID}}')

Display a list of all Control Center snapshots, with their tags.

serviced snapshot list -t

Example result, truncated to save space:

Snapshot                         Description  Tags
xm5mtezbyo2_20160211-220535.480               preupgrade-resmgr-5.2.0

The snapshot identifier is shown in the first column.

Remove the tag of the pre-update snapshot.

Replace Tag-Name with the name of the pre-update snapshot that was displayed in the previous step:
```
serviced snapshot untag ${myTenant} Tag-Name
```
Restart the update script.

Replace MAJOR.MINOR with the major and minor numbers of this version (for example, 6.4):
```
/root/MAJOR.MINOR.x/upgrade-resmgr.sh
```