Hello Is there a clean way and possibly without downtime to change the hostname and IP addresses of all the hosts in a running oVirt cluster? -- Davide Ferrari Senior Systems Engineer
Hello Davide, No, there is no support for changing host ip. How urgently do you need this? Thanks, Marcin ----- Original Message -----
From: "Davide Ferrari" <davide@billymob.com> To: "users" <users@ovirt.org> Sent: Wednesday, October 5, 2016 5:22:57 PM Subject: [ovirt-users] Change host names/IPs
Hello
Is there a clean way and possibly without downtime to change the hostname and IP addresses of all the hosts in a running oVirt cluster?
-- Davide Ferrari Senior Systems Engineer
_______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
It's not urgent, I was planning to do it in the next months so I was gathering info. Will this feature land in some new oVirt version perhaps? 2016-10-05 18:44 GMT+02:00 Marcin Mirecki <mmirecki@redhat.com>:
Hello Davide,
No, there is no support for changing host ip. How urgently do you need this?
Thanks, Marcin
----- Original Message -----
From: "Davide Ferrari" <davide@billymob.com> To: "users" <users@ovirt.org> Sent: Wednesday, October 5, 2016 5:22:57 PM Subject: [ovirt-users] Change host names/IPs
Hello
Is there a clean way and possibly without downtime to change the hostname and IP addresses of all the hosts in a running oVirt cluster?
-- Davide Ferrari Senior Systems Engineer
_______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users
-- Davide Ferrari Senior Systems Engineer
Is there a clean way and possibly without downtime to change the hostname and IP addresses of all the hosts in a running oVirt cluster?
As long as you don't change the VLANs and subnets for the hosts, you can change IPs by putting the hosts into maintenance one-by-one (so that VMs migrate to other hosts), removing them and re-adding with the new IPs. Hostnames (Except the engine's) should not matter for oVirt at all (you can register hosts to oVirt with names, but I wouldn't recommend that for production, as the DNS becomes a massive SPOF). If you change the subnet the hosts are attached to, and you have VMs that are using that subnet as well, you will not be able to do this without downtime, because the VMs will probably not have the right IP settings to allow them to communicate using the new subnet... -- Barak Korren bkorren@redhat.com RHEV-CI Team
Well, actually I want to migrate both DNS hostnames and the subnet (from a /24 to a /16) to which the ovirtmgr interface is connected. The second change is the most problematic as you say..in any case what would be the best procedure, even if it implies downtime? 2016-10-06 10:04 GMT+02:00 Barak Korren <bkorren@redhat.com>:
Is there a clean way and possibly without downtime to change the hostname and IP addresses of all the hosts in a running oVirt cluster?
As long as you don't change the VLANs and subnets for the hosts, you can change IPs by putting the hosts into maintenance one-by-one (so that VMs migrate to other hosts), removing them and re-adding with the new IPs.
Hostnames (Except the engine's) should not matter for oVirt at all (you can register hosts to oVirt with names, but I wouldn't recommend that for production, as the DNS becomes a massive SPOF).
If you change the subnet the hosts are attached to, and you have VMs that are using that subnet as well, you will not be able to do this without downtime, because the VMs will probably not have the right IP settings to allow them to communicate using the new subnet...
-- Barak Korren bkorren@redhat.com RHEV-CI Team
-- Davide Ferrari Senior Systems Engineer
On 6 October 2016 at 11:27, Davide Ferrari <davide@billymob.com> wrote:
Well, actually I want to migrate both DNS hostnames and the subnet (from a /24 to a /16) to which the ovirtmgr interface is connected. The second change is the most problematic as you say..in any case what would be the best procedure, even if it implies downtime?
Something like the following (I'm assuming you have multiple hosts...): 1. Put host in to maintenance mode 2. Remove it from oVirt 3. Change host network settings 4. Re-attach host with new setting to oVirt 5. Migrate some VMs to the new host and fix their IP settings 6. Repeat for other hosts Things to note: - If you are using hosted-engine, it will further complicate things for you, I'm not sure if and how can one change the H.E. IP. - If you are using an IP-based storage that is accessed via the same subnet, you need to ensure it is still accessible with the same name/IP from the new subnet. If you are only making this change so you can run more VMs, you can consider adding the new subnet as a new VLAN/physical LAN to the existing hosts, and keep using old /24 subnet for ovirtmgmt. It is a good idea to separate ovirtmgmt traffic from other traffic anyway... -- Barak Korren bkorren@redhat.com RHEV-CI Team
2016-10-06 14:12 GMT+02:00 Barak Korren <bkorren@redhat.com>:
Something like the following (I'm assuming you have multiple hosts...): 1. Put host in to maintenance mode 2. Remove it from oVirt 3. Change host network settings 4. Re-attach host with new setting to oVirt 5. Migrate some VMs to the new host and fix their IP settings 6. Repeat for other hosts
Well, yes, I should add some routing logic before/during migration but it should work
Things to note: - If you are using hosted-engine, it will further complicate things for you, I'm not sure if and how can one change the H.E. IP.
Yep, I'm with HE. Does anyone know if HE engine can be changed?
- If you are using an IP-based storage that is accessed via the same subnet, you need to ensure it is still accessible with the same name/IP from the new subnet.
Luckily storage is already on another vlan/network
If you are only making this change so you can run more VMs, you can consider adding the new subnet as a new VLAN/physical LAN to the existing hosts, and keep using old /24 subnet for ovirtmgmt. It is a good idea to separate ovirtmgmt traffic from other traffic anyway...
Well I have a mix of physical hosts (excluding oVirt cluster obviously) and VM that are all on the same network right now, which is the ovirtmgmt network too, and I don't want to have special routing rules only for VMs. Thanks for the tips! -- Davide Ferrari Senior Systems Engineer
I think you need to :1. Set a host into maintenance2. Uninstall3. Remove the host (if HostedEngine is running there) 4. Change the hostname & IPs5. Add the host6. Install (if HstedEngine will be running there) Best Regards,Strahil Nikolov В вторник, 14 май 2019 г., 18:05:35 ч. Гринуич-4, Davide Ferrari <davide@billymob.com> написа: Hello Is there a clean way and possibly without downtime to change the hostname and IP addresses of all the hosts in a running oVirt cluster? -- Davide Ferrari Senior Systems Engineer -- IMPORTANT! This message has been scanned for viruses and phishing links. However, it is your responsibility to evaluate the links and attachments you choose to click. If you are uncertain, we always try to help. Greetings helpdesk@actnet.se -- IMPORTANT! This message has been scanned for viruses and phishing links. However, it is your responsibility to evaluate the links and attachments you choose to click. If you are uncertain, we always try to help. Greetings helpdesk@actnet.se_______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users _______________________________________________ Users mailing list -- users@ovirt.org To unsubscribe send an email to users-leave@ovirt.org Privacy Statement: https://www.ovirt.org/site/privacy-policy/ oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/4XLQ3ZQIEHPXOF...
participants (4)
-
Barak Korren -
Davide Ferrari -
Marcin Mirecki -
Strahil Nikolov