Sometimest you might want to clean your nodes by removing some snapshots that you don’t need. Even if you did not create them, they might be there – Cassandra makes them before
scrub or before
truncate. However, removing them one by one from the whole cluster might be a pain, so I wrote a short script that does it.
Just a quick tip if you don’t like JConsole or you just prefer to have web UI for Cassandra’s JMX – there’s a quite ugly but usefull tool called MX4J and here’s how to make it work with Cassandra.
If you are a Cassandra user you’re probably experienced enough to know how to stop or restart Linux services – that’s an obvious thing. However in some cases it might be a problem if a service you turned off goes down, especially if other services have been using it. While Cassandra is very robust and crash-safe (
pkill -9 cassandra works fine ;-) ), it’s never a bad idea to do things in a way that minimizes the risk of something going wrong. The other advantage of clean Cassandra restart procedure is saving some startup time. Here is how to do it.
A few days ago I was about to upgrade Cassandra cluster from 1.1.0 (+ Authentication patch I wrote) to 1.1.6, but – a bit surprisingly – I realized that something is wrong with new Cassandra. I had no problems with creating keyspaces before, as I set proper modify-keyspaces property in access.properties, but after the upgrade it stopped to work. After a short investigation I found out that there were some significant changes in Cassandra’s Permission system which broke SimpleAuthenticator. This article is about how to make it work again.
Today I was asked to set up user authentication in Cassandra, so we could stop using the “default” user with unrestricted access only. I have to say that I was really surprised when I noticed that there’s NO out-of-the-box authentication and authorization framework in it. Luckily, it can be easily enabled in a few steps which I’m going to show you.
One important thing – SimpleAuthenticator we’re going to use is in the “examples” directory of Cassandra package. It’s because it is considered to be very simple and not very safe (it was even called a “toy” in one of Cassandra’s Jira tasks), so DO NOT rely on it as on a serious protection tool for your system. However it still fits many requirements (i.e. you don’t want user to make a mess in a Column Family he doesn’t need to work on) so you may find it useful. You have been warned.