We are using Cassandra 2.2.x version in production and currently we are manually triggering the repairs on each node. So we are planning to automate repairs using Cassandra Reaper. I don't see much documentation on it. Can anyone please list the steps how to configure the reaper in multi dc environment and use it?
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For one reason or another, I want to upgrade the version of Apache Hive from 2.3.4 to 3 on Google Cloud Dataproc(1.4.3) Spark Cluster. How can I upgrade the version of Hive but also maintain compatibility with the Cloud Dataproc tooling?
Unfortunately there's no real way to guarantee compatibility with such customizations, and there are known incompatibilities with currently released spark versions being able to talk to Hive 3.x so you'll likely run into problems unless you've managed to cross-compile all the versions you need yourself.
In any case though, the easiest way to go about it if you're only trying to get limited subsets of functionality working is simply dumping your custom jarfiles into:
/usr/lib/hive/lib/
on all your nodes via an init action. You may need to reboot your master node after doing so to update Hive metastore and Hiveserver2, or at least running:
sudo systemctl restart hive-metastore
sudo systemctl restart hive-server2
on your master node.
For Spark issues you may need your custom build of Spark as well and replace the jarfiles under:
/usr/lib/spark/jars/
I want to degrade my datastax cassandra enterprise version from 5.0.15 to 4.8.16 to list down the rollback process in case of any emergency.
Please help me to list down the process.
Before performing upgrade it's always recommended to perform backup of existing data, and if something went wrong, then you can restore data from snapshots - the precise steps will depend on how you did perform backup - via OpsCenter, or with nodetool snapshot.
See DSE upgrade guide for additional information about upgrade.
P.S. DataStax support's KB has very good article on the "manual" backup/restore - I recommend to follow it if you won't use OpsCenter for backup.
I've searched for previous versions of this question, but none seem to fit my case. I have an existing Cassandra cluster running 2.0.x. I've been allocated new VMs, so I do NOT want to upgrade my existing Cassandra nodes - rather I want to migrate to a) new VMs and b) a more current version of Cassandra.
I know for in-place upgrades, I would upgrade to the latest 2.0.x, then to the latest 2.1.x. AFAIK, there's no SSTable inconsistency here. If I go this route via addition of new nodes, I assume I would follow the datastax instructions for adding new nodes/decommissioning old nodes?
Given the above, is it possible to move from 2.0.x to 3.0.x? I know the SSTable format is different; however, if I'm adding new nodes (rather than re-using SSTables on disk), does this matter?
It seems to me that #2 has to work - otherwise, it implies that any upgrade requiring SSTable upgrades would require all nodes to be taken offline simultaneously; otherwise, there would be mixed 2.x.x and 3.0.x versions running in the same cluster at some point.
Am I completely wrong? Does anyone have any experience doing this?
Yes, it is possible to migrate data to a different environment (the new vm's with the updated Cassandra using sstableloader, but you will need C* 3.0.5 and above, as that version added support to upload sstables from previous versions.
Once that the process is completed it is recommended to execute nodetool upgradesstables to ensure that there are no incompatibilities on the data, and a nodetool cleanup.
Regarding your comment ... it implies that any upgrade requiring SSTable upgrades would require all nodes to be taken offline simultaneously;... is not true; doing the upgrade one node at a time will create a mixed cluster with nodes with the two versions as you mentioned, which is not optimal, but will allow you to avoid any downtime in production. (Note that the impact of this operation will depend on the consistency level used in your application.)
Don't worry about the migration. You can simply migrate your Cassandra 2.0.X cluster to Cassandra 3.0.X. But its better if you migrate your cluster Cassandra 2.0.X to latest Cassandra 2.X.X then Cassandra 3.0.X. You need to follow some steps-
Backup data
Uninstall present version
Install the version you want to upgrade
Restore data
As you are doing migration, you need to be careful about your data always. For the data backup and restore you can follow two ways-
Creating snapshots of your sstables and then after installing the new version of cassandra, placing the files to the data location and run sstableloader.
Backup your schema's to a .cql file and copy all the tables to .csv and then after installing the new version of cassandra, source your schema from .cql and copy all the tables from every single .csv file.
If you are fully convinced how you will complete the migration then you can write a bash script to complete the backup and restore steps.
I have a cassandra ubuntu visual cluster and need to benchmark it.
I try to do it with yahoo's ycsb (without use of maven if possible).
I use cassandra 3.0.1 but I cant find a suitbale version of ycsb.
I dont want to change to an oldest version of cassandra (ycsb latest cassandra-binding is for cassandra 2.x)
What should I do?
As suggested here, despite Cassandra 3.x is not officially supported, you can use the cassandra-cql binding.
For instance:
/bin/ycsb load cassandra-cql -threads 4 -P workloads/workloada
I just tested it on Cassandra 3.11.0 and it works for both load and run.
That said, the benchmark software to use depends on your test schedule. If you want to benchmark only Cassandra, then #gsteiner 's solution might be the best. If you want to benchmark different databases using the same tool to avoid variability, then YCSB is the right one.
I would recommend using Cassandra-stress to perform a load/performance test on your Cassandra cluster. It is very customizable, to the point that you can test distributions with different data models as well as specify how hard you want to push your cluster.
Here is a link to the Datastax documentation for it that goes into how to use the tool in depth.
https://docs.datastax.com/en/cassandra/2.1/cassandra/tools/toolsCStress_t.html
My current cassandra version is 1.1.2, it is implemented with a single node cluster, i would like to upgrade it 1.2.6 with multiple nodes in the ring. is it a proper way to migrate it directly to 1.2.6 or i should follow version by version migration.
I found the upgrading steps from this link
http://fossies.org/linux/misc/apache-cassandra-1.2.6-bin.tar.gz:a/apache-cassandra-1.2.6/NEWS.txt.
There are 9 other releases available between this two versions.
I migrate a two cluster nodes from 1.1.6 to 1.2.6 without problems and without doing version by version. Anyway, you should take a closer look into:
http://www.datastax.com/documentation/cassandra/1.2/index.html?pagename=docs&version=1.2&file=index#upgrade/upgradeC_c.html#concept_ds_smb_nyr_ck
Because there are a lot of new features from version 1.2 like the partioners maybe you need to change some configurations for your cluster.
You may directly hop on to C1.2.6.
We migrated our 4-node cluster from C1.0.9 to C1.2.8 recently without any issues. This was a rolling upgrade i.e. upgrade one node at a time and after each upgrade of a node, allow the cluster to stabilize (depends upon the traffic during upgrade)
These are the steps that we followed:
Perform below on each node,
Run Disablegossip and disablethrift, such that this node is seen as DOWN by other nodes.
flush/drain the memtables, run compaction to merge SSTables
take snapshot and enable incremental backups
This stops all the other nodes/clients from writing to this node and since memtables are flushed to disk, startup times are fast as it need not walk-through commit logs.
stop Cassandra (though this node is down, cluster is available for write/read, so zero downtime)
upgrade sstables to new storage format using sstableupgrade
install/untar Cassandra 1.2.8 on the new locations
move upgraded sstables to appropriate location
merge Cassandra.yaml from previous version and current version by a manual diff (need to detail out difference)
start Cassandra
watch the startup messages to ensure the node comes up without difficulty and is shown in the ring with mixed 1.0.x/1.2.x