Bug: copying memory settings from previous version to 5.0.3 causes traceback

[czmacleod]

Previously modifying the memory settings for omero.server was done via edits to etc/grid/templates.xml. Specifically modifying the Xmx settings for the various components.

If a templates.xml from a previous version (in this case 5.0.2) is copied into the etc/grid directory it will cause the following traceback.

Traceback (most recent call last):
  File "./current/bin/omero", line 125, in <module>
    rv = omero.cli.argv()
  File "/opt/omero/omero.server/current/lib/python/omero/cli.py", line 1276, in argv
    cli.invoke(args[1:])
  File "/opt/omero/omero.server/current/lib/python/omero/cli.py", line 823, in invoke
    stop = self.onecmd(line, previous_args)
  File "/opt/omero/omero.server/current/lib/python/omero/cli.py", line 892, in onecmd
    self.execute(line, previous_args)
  File "/opt/omero/omero.server/current/lib/python/omero/cli.py", line 974, in execute
    args.func(args)
  File "/opt/omero/omero.server/current/lib/python/omero/plugins/prefs.py", line 70, in open_and_close_config
    return func(*args, **kwargs)
  File "/opt/omero/omero.server/current/lib/python/omero/plugins/admin.py", line 670, in start
    self.startasync(args, config)
  File "/opt/omero/omero.server/current/lib/python/omero/plugins/prefs.py", line 70, in open_and_close_config
    return func(*args, **kwargs)
  File "/opt/omero/omero.server/current/lib/python/omero/plugins/admin.py", line 628, in startasync
    self.jvmcfg(args, config, verbose=False)
  File "/opt/omero/omero.server/current/lib/python/omero/plugins/prefs.py", line 70, in open_and_close_config
    return func(*args, **kwargs)
  File "/opt/omero/omero.server/current/lib/python/omero/plugins/admin.py", line 871, in jvmcfg
    rv = adjust_settings(config, template_xml)
  File "/opt/omero/omero.server/current/lib/python/omero/install/jvmcfg.py", line 413, in adjust_settings
    server, option = options[name]
KeyError: 'blitz'

Reverting the templates.xml and applying the new jvmcfg memory config settings will rectify this issue, however there doesn't seem to be anywhere this problem is documented when performing an upgrade. Users preserving etc/grid/ across minor versions will result in a server that will be unable to start.

Additionally the documentation on the memory settings (​https://www.openmicroscopy.org/site/support/omero5/sysadmins/server-performance.html#jvm-memory-settings) refers to heap_size and perm_gen with no explanation that they correlate to Xmx (Max Size) and XX:MaxPermSize. Users who previously modified Xmx settings will not have any indication that they need to set heap_size to replicate those settings.

[sbesson]

See ​https://github.com/openmicroscopy/openmicroscopy/pull/3476