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In these notes the node to be added is cld-np-19.cloud.pd.infn.it

Disable the node so that no new VMs will be scheduled on this host. Instructions: Disable/Enable a compute node howto

Migrate the instances on this compute node to other hypervisors. Instructions: Migrate an instance howto (warning: there was once a problem with live-block migration; we therefore decided to always use cold migration)

Just in case save the file /etc/iscsi/initiatorname.iscsi and the output of "ifconfig" command in cld-ctrl-01:/root/Backup/<hostname>

Reinstall the host with CentOS8 stream using Foreman . Move and move the host to the 'hosts_all' hostgroup

As Operating System choose: CentOS Stream 8

As Media choose: CentOS-Stream-local

As Partition table select

• "Kickstart default - swap 128 GB" (if this machine has 2 disks: one for the OS and one for the VM ephemeral storage). WARNING this will scratch also the second disk. Chidere a Traldi cosa usare per non scratchare il secondo disco
• "Kickstart default - swap 128 GB 1 disk 2 parts" (if this machine has only one disk for both the OS and the VM ephemeral storage

Once the machine is reinstalled make Make sure that SElinux is disabled

...

Configure the data network (and, for Unipd nodes, also the storage one), e.g.:

nmcli con mod eno3 ipv4.method manual ipv4.addr "192.168.61.129/24" 
nmcli con mod eno3 802-3-ethernet.mtu 9000 
nmcli con up eno3
nmcli con mod eno3 connection.autoconnect yes

...

puppet agent -t

If this host has 2 disks (one for the OS and one for the ephemeral storage disk), move /var/lib/nova/instances to the second disk

Start and enablepuppet:

systemctl start puppet; systemctl enable puppet

...

Verify that a ssh from root@cld-log to root@<hostname> works without requiring passwordroot@cld-np-19 works and from  nagios@cld-nagios to nagios@cld-np-19  without requiring password

Reboot the node.

Enable the host. From cld-ctrl-01 after having sourced admin-openrc.sh:

openstack compute service set --enable cld-np-19.cloud.pd.infn.it nova-compute

Force the execution of the "VM network and volume" nagios sensor