There is a bug related to KVM upgrade: CLOUDSTACK-4405. The main issue is
related to guest network bridge name schema is changed, thus migrate vm, create
new vm will have problem after upgraded to 4.2.
If you are using basic network, then don't need to do the following steps.
The proposed upgrade paths are:
1. Stick to old network name in 4.2. You can set
"network.bridge.name.schema=3.0" in /etc/cloudstack/agent/agent.properties
2. Upgrade to new network name schema, need to do the following steps:
a. Install 4.2 cloudstack agent on each kvm host
b. Run "cloudstack-agent-upgrade". This script will upgrade all the
existing bridge name to new bridge name.
c. install a libvirt hook:
c1. mkdir /etc/libvirt/hooks
c2. cp /usr/share/cloudstack-agent/lib/libvirtqemuhook
/etc/libvirt/hooks/qemu
c3. chmod +x /etc/libvirt/hooks/qemu
c4. service libvirtd restart
c5. service cloudstack-agent restart
The potential issues if you are using above upgrade path 2:
1. If you are using multiple physical bridges, other than the one specified in
"guest.network.device" in /etc/cloudstack/agent/agent.properties, then the vm
live migration may have problem.
2. Advanced zone with security group, wont' work.
3. may have old iptables rules left on kvm host, it shouldn't impact guest
connectivity though.
