Change the management network gateway on a host

Applicable scenario

• Product: ZCF
• Component: ZStack Cloud
• Trigger condition: planned change of the management network gateway

Problem statement

This article describes how to change the management network gateway on a ZStack host when the customer needs to migrate to a new gateway (e.g. from 10.20.21.255 to 10.20.21.254). The procedure works on the management bridge br_bond0 and requires strict sequencing to avoid losing access to the host.

Solution steps

Preparation

1. Confirm that all VMs on the cluster are in the Stopped state. Live migration is not possible because the change affects the host's management network.
2. Back up the ZStack database:

   zstack-ctl dump_mysql

3. Change the management network gateway of the hosts in the cluster. Use out-of-band management or the storage network to change the management network gateway on the other nodes, preventing a network outage if the change is incorrect.

Solution steps

Step 1. Edit the bridge configuration

On the target host, edit the bridge configuration file:

vim /etc/sysconfig/network-scripts/ifcfg-br_bond0

Update the following fields. Example values:

DEVICE=br_bond0
NAME=br_bond0
TYPE=Bridge
ONBOOT=yes
BOOTPROTO=static
IPV6INIT=no
IPV6_AUTOCONF=no
DELAY=5
STP=no
IPADDR=10.20.21.1
NETMASK=255.255.255.0
GATEWAY=10.20.21.254    # new gateway

Step 2. Restart the network service

systemctl restart network

Step 3. Verify

Reconnect to the host using the management network with the new gateway. Confirm:

• The host is reachable on its management IP.
• The host can reach the management node and the default gateway.
• In the ZStack UI, the host status is Connected and the management network is shown with the new gateway.