By default, mlockall() is enabled for ovs-vswitchd. This results in
locking all of ovs-vswitchd's process memory into physical RAM and
prevents paging. This enables network performance but can lead to
memory exhaustion in memory-constrained environments. To disable
mlockall(), the disable-mlockall charm config option can be set to
True. If unset, disable-mlockall charm config will result in
disabling mlockall if running in a container.
The drop_config.append(OVS_DEFAULT) logic is no longer used as
it prevents a rewrite of the config template when charm config is
reset. For example, the new behavior results in
/etc/default/openvswitch-switch being written with comments only
when the corresponding config options are disabled (see template),
resulting in openvswitch-switch being restarted.
Due to the removal of drop_config.append(OVS_DEFAULT), pause/resume
actions need to explicitly remove openswitch-switch to maintain
prior behavior for non-DPDK deployments. In other words, pause/resume
will not restart openvswitch-switch.
Closes-Bug: #1906280
Related-Bug: #1908615
Change-Id: I2e3153e90c7a4a1b7dec7d6df427b33a449f414d
282f6af3db