This guide explains how to reinstall a compute node from Centos8 Stream-Yoga to AlmaLinux9-Yoga
In the following instructions the node cld-np-19, an INFN node, is the one to be reinstalled
First of all take note of the IP addresses used by the VM for the management and data networks (192.168.60.x and 192.168.61.x) ) and the relevant interfaces
[root@cld-np-19 ~]# nmcli eno1: connected to System eno1 "Intel X710" ethernet (i40e), 34:E6:D7:F5:53:0D, hw, port e4434b3a8890, mtu 1500 ip4 default inet4 192.168.60.129/24 route4 192.168.60.0/24 metric 100 route4 default via 192.168.60.254 metric 100 inet6 fe80::36e6:d7ff:fef5:530d/64 route6 fe80::/64 metric 1024 eno3: connected to eno3 "Intel X710" ethernet (i40e), 34:E6:D7:F5:53:0F, hw, port e4434b3a8892, mtu 9000 inet4 192.168.61.129/24 route4 192.168.61.0/24 metric 101 inet6 fe80::65:ec7c:7325:3bec/64 route6 fe80::/64 metric 1024 ... ...
Then disable the compute node, so that no new VMs will be instantiated on this compute node:
openstack compute service set --disable cld-np-19.cloud.pd.infn.it nova-compute
To check if the compute node was actually disabled:
openstack compute service list
Then finds all the virtual machines instantiated on this compute node:
openstack server list --all --host cld-np-19.cloud.pd.infn.it
Then migrate each VM instantiated on this compute node to other hypervisors.
To avoid the migration of the same virtual machine multiple times, please migrate the VM on a compute node that was already migrated to AlmaLinux9
The migration of a virtual machine usually requires a downtime (~ 15') of that VM, unless the VM was created using a volume. So before migrating the VM you must agree this operation with the relevant owner.
E.g. to find the owner of a VM with UUID be832766-7996-4ccf-a9c1-5eec2e5f8fd3:
[root@cld-ctrl-01 ~]# openstack server show be832766-7996-4ccf-a9c1-5eec2e5f8fd3 | grep user_id
| user_id | 7681252c430040e7bb96c7c4f7c88464 |
[root@cld-ctrl-01 ~]# openstack user show 7681252c430040e7bb96c7c4f7c88464
+---------------------+----------------------------------+
| Field | Value |
+---------------------+----------------------------------+
| domain_id | default |
| email | Ysabella.Ong@lnl.infn.it |
| enabled | True |
| id | 7681252c430040e7bb96c7c4f7c88464 |
| name | ysaong@infn.it |
| options | {} |
| password_expires_at | None |
+---------------------+----------------------------------+
To migrate a virtual machine to another compute node, there are two possible procedures:
- Procedure to be used if the VM was created using a volume (the migration procedure doesn't require a downtime)
- Procedure to be used if the VM was created using ephemeral storage (the migration procedure requires a downtime)
Once there are no more VMs on that compute node, reinstall the node with AlmaLinux9 using foreman
- The hostgroup must be hosts_all
- The kickstart to be used must be TBC
- TBC
When the node restart after the update, make sure that SELinux is disabled:
[root@cld-np-19 ~]# getenforce Disabled
Then do an update of the packages (probabily only puppet will be updated):
[root@cld-np-19 ~]# yum clean all [root@cld-np-19 ~]# yum update -y
Once the node has been reinstalled with AlmaLinux9, configure the data network
TBC
The address to be used must be the original one
MTU must be 9000
If this is a DELL host, reinstall DELL OpenManage, as explained here
Check on Nagios that the relevant checks get green
Then configure the node as Openstack compute node using puppet
Stop puppet:
systemctl stop puppet
In foreman move the host under the ComputeNode-Prod_Yoga hostgroup
Run puppet manually:
puppet agent -t
If the configuration fails reporting
error: "net.bridge.bridge-nf-call-ip6tables" is an unknown key error: "net.bridge.bridge-nf-call-iptables" is an unknown key error: "net.bridge.bridge-nf-call-arptables" is an unknown key
then please issue:
modprobe br_netfilter
and then rerun puppet
Start and enablepuppet:
systemctl start puppet; systemctl enable puppet
Enable the checks in Nagios for this host
Wait till all checks are ok (in particular the VM network and volume one: remember to enable the node just for the time to force the run from Nagios; othwerwise the check will fail.)
- Add this node in the following scripts on cld-ctrl-01: /usr/local/bin/display_usage_of_hypervisors.sh, /usr/local/bin/host_aggregate.sh, /usr/local/bin/new_project.sh, /usr/local/bin/free_resources_compute_nodes.sh
- Add this node in the /etc/cron.daily/vm-log.sh script on cld-log
- Create the directory /var/disk-iscsi/qemu/cld-np-19 in cld-log
- Verify that a ssh from root@cld-log to root@cld-np-19 works without requiring password
Stop puppet on the 2 controller nodes:
systemctl stop puppet
Add the new compute node in cld-config:/var/puppet/puppet_yoga/controller_yoga/templates/aai_settings.py.erb
Run puppet on the first controller node (this will trigger a restart of httpd):
puppet agent -t
Run puppet on the second controller node (this will trigger a restart of httpd):
puppet agent -t
Start puppet on the two controller nodes:
systemctl start puppet
Enable the host:
openstack compute service set --enable cld-np-19.cloud.pd.infn.it nova-compute
- Add the host to the 'admin' aggregate
Run the aggregate_manage.sh script to add the node in the relevant hostgroups, e.g.:
/usr/local/bin/aggregate_manage.sh add cld-np-19.cloud.pd.infn.it INFN