Dmitry, You are welcome to create a pull request against the documentation to make it more precise.
Thanks, Roman On Friday, January 10, 2014, Dmitriy Novakovskiy wrote: > Thanks guys. That helped a lot. > > --- > Regards, > Dmitriy > > > On Fri, Jan 10, 2014 at 5:44 AM, Miroslav Anashkin <[email protected] > > wrote: > > Hi Dmitriy, > > A1. Yes, MySQL+Galera is true master-master solution. While it is possible > and, in case of 6+ nodes even recommended, to set 1-2 Galera nodes as > slaves - for additional data consistency. > Previous Fuel versions use HAProxy as MySQL managing solution. > In case of Mirantis OpenStack (starting from 3.0 or 3.1) MySQL+Galera > cluster is managed by Pacemaker. > There is no single master node in Galera cluster at all - there are nodes > with most recent data replica and nodes which still have to sync with this > recent replica. > Workflow is simple. Node serves new data changing request and increases > its UUID number. All the other nodes must synchronize data with all the > nodes with UUID greater than current. > > A2. Yes, CEPH monitors are also master-master. One of them is > periodically becomes a leader. Leader is the node, which got the most > recent cluster map replica first. Other monitor nodes must sync they > cluster map with current leader. Every monitor node already synced with > leader becomes provider and leader knows which nodes are currently > providers. So, leader also tells the other nodes which provider each of > them should use to get data from. > CEPH monitor synchronization algorithm works similar way as Galera, but > CEPH nodes are parted by functionality to monitor nodes and data storage > nodes. In turn, every Galera node has all the same service set on each node. > So, CEPH monitor nodes only manage where the data should be actually > stored and maintain data consistency between OSD nodes. > > > A3. Additionally to the previous answerers I may add that Neutron is a > router among the other functionality. It is the reason why there are single > entry points. > > > On Fri, Jan 10, 2014 at 12:18 PM, Dmitriy Novakovskiy < > [email protected]> wrote: > > Hi guys, > > I'm currently kicking off a a project with new customer, and stumbled on > some holes in my understanding of Mirantis HA architecture. > > Can you please help me understand the following: > > Q1. MySQL + Galera - is it an active/active HA? I was told/tend to think > "yes", but want to understand it better. A simple workflow example would > help > > Q2. ceph-mon on controllers - same question as Q1 > > Q3. Neutron - is it in active/standy HA? I got this understanding from > docs and want to understand why. I was told that Grizzly and Havanna > support multiple l3 agents, but we don't leverage it on some reason in Fuel. > > Thanks a lot in advance > > --- > Regards, > Dmitriy > > -- > Mailing list: https://launchpad.net/~fuel-dev > Post to : [email protected] > Unsubscribe : https://launchpad.net/~fuel-dev > More help : https://help.launchpad.net/ListHelp > > > > > -- > > *Kind Regards* > > *Miroslav Anashkin**L2 support engineer**,* > *Mirantis Inc.* > >
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