move clean-ephemeral to lxc pre-start hook

basic/srv/vm/cli.py

@@ -44,6 +44,10 @@ parser_disable_autostart.add_argument('app', help='Application name')
 parser_rebuild_issue = subparsers.add_parser('rebuild-issue', help='Rebuilds /etc/issue using current settings - used on VM startup')
 parser_rebuild_issue.set_defaults(action='rebuild-issue')
 
+parser_clean_ephemeral = subparsers.add_parser('clean-ephemeral', help='Cleans container ephemeral layer. Intended to be used with LXC hooks')
+parser_clean_ephemeral.add_argument('lxc', nargs=argparse.REMAINDER)
+parser_clean_ephemeral.set_defaults(action='clean-ephemeral')
+
 parser_register_container = subparsers.add_parser('register-container', help='Register and assigns IP to an application container. Intended to be used with LXC hooks')
 parser_register_container.add_argument('lxc', nargs=argparse.REMAINDER)
 parser_register_container.set_defaults(action='register-container')
@@ -102,6 +106,8 @@ elif args.action == 'disable-autostart':
     mgr.disable_autostart(args.app)
 elif args.action == 'rebuild-issue':
     mgr.rebuild_issue()
+elif args.action == 'clean-ephemeral':
+    mgr.clean_ephemeral()
 elif args.action == 'register-container':
     mgr.register_container()
 elif args.action == 'unregister-container':

basic/srv/vm/mgr/__init__.py

@@ -211,6 +211,11 @@ class VMMgr:
             raise validator.InvalidValueException('app', app)
         subprocess.run(['/sbin/rc-update', 'del', app])
 
+    def clean_ephemeral(self):
+        # Remove ephemeral layer data
+        app = os.environ['LXC_NAME']
+        tools.clean_ephemeral_layer(app)
+
     def register_container(self):
         # Set IP of a container based on values given via lxc.hook.start-host hook
         app = os.environ['LXC_NAME']
@@ -218,15 +223,13 @@ class VMMgr:
         ip = tools.get_unused_ip()
         tools.update_hosts_lease(ip, app)
         tools.set_container_ip(pid, ip)
-        # Remove ephemeral layer data
-        tools.remove_ephemeral_layer(app)
 
     def unregister_container(self):
         # Unset IP of a container based on values given via lxc.hook.post-stop hook
         app = os.environ['LXC_NAME']
         tools.update_hosts_lease(None, app)
         # Remove ephemeral layer data
-        tools.remove_ephemeral_layer(app)
+        tools.clean_ephemeral_layer(app)
 
     def register_proxy(self, app, reload_nginx=True):
         # Rebuild nginx configuration using IP of referenced app container and reload nginx

basic/srv/vm/mgr/tools.py

@@ -155,7 +155,7 @@ def set_container_ip(pid, ip):
     cmd = 'ip addr add {}/16 broadcast 172.17.255.255 dev eth0 && ip route add default via 172.17.0.1'.format(ip)
     subprocess.run(['nsenter', '-a', '-t', pid, '--', '/bin/sh', '-c', cmd])
 
-def remove_ephemeral_layer(app):
+def clean_ephemeral_layer(app):
     layer = os.path.join('/var/lib/lxc', app, 'delta0')
     if os.path.exists(layer):
         for item in os.scandir(layer):

zz-extra/lxc-build

@@ -43,6 +43,7 @@ lxc.console.logfile = /var/log/lxc/{name}.log
 # Other
 lxc.arch = x86_64
 lxc.cap.drop = sys_admin
+lxc.hook.pre-start = /usr/bin/vmmgr clean-ephemeral
 lxc.hook.start-host = /usr/bin/vmmgr register-container
 lxc.hook.post-stop = /usr/bin/vmmgr unregister-container
 lxc.include = /usr/share/lxc/config/common.conf