Thanks for the info Alex! I read https://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsSwitchSnitch.html but still have a few questions:
Our clusters are comprised of 2 DCs with no rack configuration, RF=3 on each DC. In this scenario, if I wish to seamlessly change the snitch with 0 downtime, do I need to add the cassandra-rackdc.properties file, change the snitch in cassandra.yaml and restart one by one? Will this method cause problems? Thanks! On Wed, Feb 27, 2019 at 12:18 PM Alexander Dejanovski < a...@thelastpickle.com> wrote: > You'll be fine with the SimpleSnitch (which shouldn't be used either > because it doesn't allow a cluster to use multiple datacenters or racks). > Just change the IP and upon restart the node will redeclare itself in the > ring. If your node is a seed node, you'll need to update your seed list > across the cluster. > > On Wed, Feb 27, 2019 at 10:52 AM wxn...@zjqunshuo.com < > wxn...@zjqunshuo.com> wrote: > >> I'm using SimpleSnitch. I have only one DC. Is there any problem to >> follow the below procedure? >> >> -Simon >> >> *From:* Alexander Dejanovski <a...@thelastpickle.com> >> *Date:* 2019-02-27 16:07 >> *To:* user <user@cassandra.apache.org> >> *Subject:* Re: Question on changing node IP address >> >> I confirm what Oleksandr said. >> Just stop Cassandra, change the IP, and restart Cassandra. >> If you're using the GossipingPropertyFileSnitch, the node will redeclare >> its new IP through Gossip and that's it. >> If you're using the PropertyFileSnitch, well... you shouldn't as it's a >> rather dangerous and tedious snitch to use. But if you are, it'll require >> to change the file containing all the IP addresses across the cluster. >> >> I've been changing IPs on a whole cluster back in 2.1 this way and it >> went through seamlessly. >> >> Cheers, >> >> On Wed, Feb 27, 2019 at 8:54 AM Oleksandr Shulgin < >> oleksandr.shul...@zalando.de> wrote: >> >>> On Wed, Feb 27, 2019 at 4:15 AM wxn...@zjqunshuo.com < >>> wxn...@zjqunshuo.com> wrote: >>> >>>> >After restart with the new address the server will notice it and log a >>>> warning, but it will keep token ownership as long as it keeps the old host >>>> id (meaning it must use the same data directory as before restart). >>>> >>>> Based on my understanding, token range is binded to host id. As long as >>>> host id doesn't change, everything is ok. Besides data directory, any other >>>> thing can lead to host id change? And how host id is caculated? For >>>> example, if I upgrade Cassandra binary to a new version, after restart, >>>> will host id change? >>>> >>> >>> I believe host id is calculated once the new node is initialized and >>> never changes afterwards, even through major upgrades. It is stored in >>> system keyspace in data directory, and is stable across restarts. >>> >>> -- >>> Alex >>> >>> -- >> ----------------- >> Alexander Dejanovski >> France >> @alexanderdeja >> >> Consultant >> Apache Cassandra Consulting >> http://www.thelastpickle.com >> >> -- > ----------------- > Alexander Dejanovski > France > @alexanderdeja > > Consultant > Apache Cassandra Consulting > http://www.thelastpickle.com >
