Network down in VMs after update of cloud init or CentOS
After updating the cloud-init package to version >=0.7.7, which is used in our official CentOS images, the network interface name in your VMs may change.
WARNING: This may lead to network interfaces being down after reboot! Please be aware, that this may also affect correct operation of your firewall and applications.
The new cloud-init package reads the interface name from the VM configuration on SmartOS. The default name of network interfaces in KVM virtual machines in Danube Cloud is net<id>. However, the old cloud-init ignored this and usually the NICs were named eth<id> in your Linux guest OS. Our old CentOS images have a network auto-configuration in /etc/rc.d/rc.local, which expects only interfaces named eth<id>.
Additionally, cloud-init (at least version 0.7.9) attempts to configure the network interfaces automatically. However, it tries to use a static IP configuration (read from the SmartOS datasource), which is wrong - the NICs in the guest OS should be configured via DHCP.
- esdc-mgmt <= 2.6.4
- esdc-mon <= 2.6.4
- centos-7 <= 20170724
- centos7-desktop <= 20170724
- gitlab-ce <= 20170724
The suggested fix is to disable network configuration in cloud-init. This can be achieved by adding the following lines into /etc/cloud/cloud.cfg:
network:
config: disabledIf you've already rebooted and cannot access your VM, you can log in via the Danube Cloud HTML console and perform the fix there.
