44 lines
1.4 KiB
ReStructuredText
44 lines
1.4 KiB
ReStructuredText
Migration from ML2/OVS to ML2/OVN
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=================================
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Proof-of-concept ansible script for migrating an OpenStack deployment
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that uses ML2/OVS to OVN.
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If you have a tripleo ML2/OVS deployment then please see the folder
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``tripleo_environment``
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Prerequisites:
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1. Ansible 2.2 or greater.
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2. ML2/OVS must be using the OVS firewall driver.
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To use:
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1. Create an ansible inventory with the expected set of groups and variables
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as indicated by the hosts-sample file.
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2. Run the playbook::
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$ ansible-playbook migrate-to-ovn.yml -i hosts
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Testing Status:
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- Tested on an RDO cloud on CentOS 7.3 based on Ocata.
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- The cloud had 3 controller nodes and 6 compute nodes.
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- Observed network downtime was 10 seconds.
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- The "--forks 10" option was used with ansible-playbook to ensure
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that commands could be run across the entire environment in parallel.
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MTU:
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- If migrating an ML2/OVS deployment using VXLAN tenant networks
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to an OVN deployment using Geneve for tenant networks, we have
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an unresolved issue around MTU. The VXLAN overhead is 30 bytes.
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OVN with Geneve has an overhead of 38 bytes. We need the tenant
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networks MTU adjusted for OVN and then we need all VMs to receive
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the updated MTU value through DHCP before the migration can take
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place. For testing purposes, we've just hacked the Neutron code
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to indicate that the VXLAN overhead was 38 bytes instead of 30,
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bypassing the issue at migration time.
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