Need an option to not upgrade the kernel upon reboot

[Senthilnathan Murugappan]

On VM reboot in azure cloud it seems the ubuntu kernel gets updated and so vrouter insertion fails upon reboot.

root@ms-compute-3:~# modprobe vrouter
modprobe: FATAL: Module vrouter not found in directory /lib/modules/4.4.0-130-generic

root@ms-compute-3:~# ls /lib/modules/4.4.0-
4.4.0-130-generic/ 4.4.0-21-generic/ 4.4.0-65-generic/

root@ms-compute-3:~# find /lib/modules/ -name vrouter.ko
/lib/modules/4.4.0-65-generic/updates/dkms/vrouter.ko

root@ms-compute-3:~# uname -a
Linux ms-compute-3 4.4.0-130-generic #156-Ubuntu SMP Thu Jun 14 08:53:28 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

On the VM which is not rebooted..
root@ms-compute-1:~# uname -a
Linux ms-compute-1 4.4.0-65-generic #86-Ubuntu SMP Thu Feb 23 17:49:58 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

root@ms-compute-1:~# ls /lib/modules
4.4.0-21-generic 4.4.0-65-generic

If possible, we need to have a workaround to not upgrade the kernel in our multicloud or ansible-deployer playbooks

[Senthilnathan Murugappan (msenthil)]

Workaround:
After compute restart do 'docker-compose down' and 'docker-compose up -d' under /etc/contrail/vrouter

[Damian Rakowski (attil)]

I have created a PR that should block kernel upgrades, but we have to discuss it's pros and cons before merging. https://github.com/Juniper/contrail-multi-cloud/pull/211/files