It’s self respond. Step3 is wrong.
Even if it was a SimpleSnitch, changing the dc information will not start CassandraDaemon with the error log. ERROR [main] 2018-09-11 18:36:30,272 CassandraDaemon.java:708 - Cannot start node if snitch's data center (pg1) differs from previous data center (datacenter1). Please fix the snitch configuration, decommission and rebootstrap this node or use the flag -Dcassandra.ignore_dc=true. > On 11 Sep 2018, at 2:25 PM, Eunsu Kim <eunsu.bil...@gmail.com> wrote: > > Hello > > Thank you for your responses. > > I’ll share my adding datacenter plan. If you see problems, please respond. > > The sentence may be a little awkward because I am so poor at English that I > am being helped by a translator. > > I've been most frequently referred to.(https://medium.com/p/465e9bf28d99 > <https://medium.com/p/465e9bf28d99>) Thank you for your cleanliness. (Pradeep > Chhetri) > > I will also upgrade the version as Alain Rodriguez's advice. > > ———— > > Step 1. Stop all existing clusters. (My service is paused.) > > Step 2. Install Cassandra 3.11.3 and copy existing conf files. > > Step 3. Modify cassandra-rackdc.properties for existing nodes. dc=mydc1 > rack=myrack1 > Q. I think this modification will not affect the existing data because > it was SimpleSnitch before, right? > > Step 4. In the caseandra.yaml of existing nodes, endpoint_snitch is changed > to GossippingPropertyFileSnitch. > > Step 5. Restart the Cassandra of the existing nodes. (My service is resumed.) > > Step 6. Change the settings of all existing clients to DCAwareRobinPolicy and > refer to mydc1. Consistency level is LOCAL_ONE. And rolling restart. > Q. Isn't it a problem that at this point, DCAwareRobinPolicy and > RoundRobinPolicy coexist? > > Step 7. Alter my keyspace and system keyspace(system_distributed, > system_traces) : SimpleStrategy(RF=2) -> { 'class' : > 'NetworkTopologyStrategy', ‘mydc1’ : 2 } > > Step 8. Install Cassandra in a new cluster, copying existing conf files, and > setting it to Cassandra-racdc.properties. dc=mydc2 rack=myrack2 > > Step 9. Adding a new seed node to the cassandra.yaml of the existing cluster > (mydc1) and restart. > Q1. Must I add the new seed nodes in five all existing nodes? > Q2. Don't I need to update the seed node settings of the new cluster > (mydc2)? > > Step 10. Alter my keyspace and system keyspace(system_distributed, > system_traces) : { 'class' : 'NetworkTopologyStrategy', ‘mydc1’ : 1, ‘mydc2’ > : 1 } > > Step 11. Run 'nodetool rebuild — mydc1’ in turn, in the new node. > > ——— > > > I'll run the procedure on the development envrionment and share it. > > Thank you. > > > > >> On 10 Sep 2018, at 10:26 PM, Pradeep Chhetri <prad...@stashaway.com >> <mailto:prad...@stashaway.com>> wrote: >> >> Hello Eunsu, >> >> I am going through the same exercise at my job. I was making notes as i was >> testing the steps in my preproduction environment. Although I haven't tested >> end to end but hopefully this might help you: >> https://medium.com/p/465e9bf28d99 <https://medium.com/p/465e9bf28d99> >> >> Regards, >> Pradeep >> >> On Mon, Sep 10, 2018 at 5:59 PM, Alain RODRIGUEZ <arodr...@gmail.com >> <mailto:arodr...@gmail.com>> wrote: >> Adding a data center for the first time is a bit tricky when you haven't >> been considering it from the start. >> >> I operate 5 nodes cluster (3.11.0) in a single data center with >> SimpleSnitch, SimpleStrategy and all client policy RoundRobin. >> >> You will need: >> >> - To change clients, make them 'DCAware'. This depends on the client, but >> you should be able to find this in your Cassandra driver (client side). >> - To change clients, make them use 'LOCAL_<WHATEVER>' consistency >> ('LOCAL_ONE'/'LOCAL_QUORUM' being the most common). >> - To change 'SimpleSnitch' for 'EC2Snitch' or 'GossipingPropertyFileSnitch' >> for example, depending on your context/preference >> - To change 'SimpleStrategy' for 'NetworkTopologyStrategy' for all the >> keyspaces, with the desired RF. I take the chance to say that switching to 1 >> replica only is often a mistake, you can indeed have data loss (which you >> accept) but also service going down, anytime you restart a node or that a >> node goes down. If you are ok with RF=1, RDBMS might be a better choice. >> It's an anti-pattern of some kind to run Cassandra with RF=1. Yet up to you, >> this is not our topic :). In the same kind of off-topic recommendations, I >> would not stick with C*3.11.0, but go to C*3.11.3 (if you do not perform >> slice delete, there is still a bug with this apparently) >> >> So this all needs to be done before starting adding the new data center. >> Changing the snitch is tricky, make sure that the new snitch uses the racks >> and dc names currently in use in your cluster for the current cluster, if >> not the data could not be accessible after the configuration change. >> >> Then the procedure to add a data center is probably described around. I know >> I did this detailed description in 2014, here it is: >> https://mail-archives.apache.org/mod_mbox/cassandra-user/201406.mbox/%3cca+vsrlopop7th8nx20aoz3as75g2jrjm3ryx119deklynhq...@mail.gmail.com%3E >> >> <https://mail-archives.apache.org/mod_mbox/cassandra-user/201406.mbox/%3cca+vsrlopop7th8nx20aoz3as75g2jrjm3ryx119deklynhq...@mail.gmail.com%3E>, >> but you might find better/more recent documentation than this one for this >> relatively common process, like the documentation you linked. >> >> If you are not confident or have doubts, you can share more about the >> context and post your exact plan, as I did years ago in the mail previously >> linked. People here should be able to confirm the process is ok before you >> move forward, giving you an extra confidence. >> >> C*heers, >> ----------------------- >> Alain Rodriguez - @arodream - al...@thelastpickle.com >> <mailto:al...@thelastpickle.com> >> France / Spain >> >> The Last Pickle - Apache Cassandra Consulting >> http://www.thelastpickle.com <http://www.thelastpickle.com/> >> >> Le lun. 10 sept. 2018 à 11:05, Eunsu Kim <eunsu.bil...@gmail.com >> <mailto:eunsu.bil...@gmail.com>> a écrit : >> Hello everyone >> >> I operate 5 nodes cluster (3.11.0) in a single data center with >> SimpleSnitch, SimpleStrategy and all client policy RoundRobin. >> >> At this point, I am going to create clusters of the same size in different >> data centers. >> >> I think these two documents are appropriate, but there is confusion because >> they are referenced to each other. >> >> https://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsAddDCToCluster.html >> >> <https://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsAddDCToCluster.html> >> https://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsSwitchSnitch.html >> >> <https://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsSwitchSnitch.html> >> >> Anyone who can clearly guide the order? Currently RF is 2 and I want to have >> only one replica in the NetworkTopologyStrategy. >> A little data loss is okay. >> >> Thank you in advanced.. >> >> >> >> >> >> >> >
