Bootstrap checks

If you are binding to a network reachable IP address, CrateDB performs a number of bootstrap checks during startup. These checks examine your setup and will prevent startup if a problem is detected.

This best practices guide is intended to help you configure your setup so that CrateDB passes the bootstrap checks and can perform optimally.

If you are binding to the loopback address, the bootstrap checks will not be run, but it is still a good idea to follow these instructions.

Tip

If you are using Docker, these checks are dependent on the host system. You must configure the host system appropriately if you wish to run CrateDB on Docker. Consult the additional documentation on Docker resource constraints for more information.

Table of contents

System settings

Official packages

If you are using one of the official packages, all of the necessary operating system configuration is handled for you.

Tarball

If you have installed CrateDB from a tarball, you must manually configure your operating system.

Here’s what needs to be configured:

  • File descriptors
    • Set hard and soft limit to unlimited
  • Memory lock
    • Set hard and soft limit to unlimited
  • Threads
    • Set hard and soft limit to 4096 (CrateDB versions < 3.0.0 will also work with 2048)
  • Virtual memory
    • Set hard and soft limit to unlimited (on Linux only)
  • Memory map
    • Set limit to 262144 (on Linux only)

You might be able to set these limits per process or per user, depending on your operating system and setup. And for this to take effect, you may also have to set these limits for the superuser.

Linux

If you’re running Linux, you can perform the necessary configuration by following these instructions.

Edit /etc/security/limits.conf and configure these lines:

crate soft nofile unlimited
crate hard nofile unlimited

crate soft memlock unlimited
crate hard memlock unlimited

crate soft nproc 4096
crate hard nproc 4096

crate soft as unlimited
crate hard as unlimited

Here, crate is the user that runs the CrateDB daemon.

Edit /etc/sysctl.conf and configure:

vm.max_map_count = 262144

To apply this change, run:

$ sudo sysctl -p

This command will this reload all settings from /etc/sysctl.conf.

Tip

Alternatively, vm.max_map_count can be set directly, like so:

$ sysctl -w vm.max_map_count=262144

Note, however, this setting will be reset to the value in /etc/sysctl.conf when your system next boots.

Garbage collection

CrateDB uses the CMS garbage collector and this should not be changed.

Warning

If you use a different JVM garbage collector you may encounter serious performance degradation or even data corruption.