CentOS installation

This guide describes the fastest way to install Graylog on CentOS 7. All links and packages are present at the time of writing but might need to be updated later on.

Warning

This setup should not be done on publicly exposed servers. This guide does not cover security settings!

Prerequisites

Taking a minimal server setup as base will need this additional packages:

$ sudo yum install java-1.8.0-openjdk-headless.x86_64

If you want to use pwgen later on you need to Setup EPEL on your system with sudo yum install epel-release and install the package with sudo yum install pwgen.

MongoDB

Installing MongoDB on CentOS should follow the tutorial for RHEL and CentOS from the MongoDB documentation. First add the repository file /etc/yum.repos.d/mongodb-org-3.2.repo with the following contents:

[mongodb-org-3.2]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/3.2/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-3.2.asc

After that, install the latest release of MongoDB with sudo yum install mongodb-org.

Additionally, run these last steps to start MongoDB during the operating system’s boot and start it right away:

$ sudo chkconfig --add mongod
$ sudo systemctl daemon-reload
$ sudo systemctl enable mongod.service
$ sudo systemctl start mongod.service

Elasticsearch

Graylog 2.0.0 and higher requires Elasticsearch 2.x, so we took the installation instructions from the Elasticsearch installation guide.

First install the Elastic GPG key with rpm --import https://packages.elastic.co/GPG-KEY-elasticsearch then add the repository file /etc/yum.repos.d/elasticsearch.repo with the following contents:

[elasticsearch-2.x]
name=Elasticsearch repository for 2.x packages
baseurl=https://packages.elastic.co/elasticsearch/2.x/centos
gpgcheck=1
gpgkey=https://packages.elastic.co/GPG-KEY-elasticsearch
enabled=1

followed by the installation of the latest release with sudo yum install elasticsearch.

Make sure to modify the Elasticsearch configuration file (/etc/elasticsearch/elasticsearch.yml) and set the cluster name to graylog additionally you need to uncomment (remove the # as first character) the line:

cluster.name: graylog

After you have modified the configuration, you can start Elasticsearch:

$ sudo chkconfig --add elasticsearch
$ sudo systemctl daemon-reload
$ sudo systemctl enable elasticsearch.service
$ sudo systemctl restart elasticsearch.service

Graylog

Now install the Graylog repository configuration and Graylog itself with the following commands:

$ sudo rpm -Uvh https://packages.graylog2.org/repo/packages/graylog-2.1-repository_latest.rpm
$ sudo yum install graylog-server

Follow the instructions in your /etc/graylog/server/server.conf and add password_secret and root_password_sha2. These settings are mandatory and without them, Graylog will not start!

You need to use the following command to create your root_password_sha2:

echo -n yourpassword | sha256sum

To be able to connect to Graylog you should set rest_listen_uri and web_listen_uri to the public host name or a public IP address of the machine you can connect to. More information about these settings can be found in Configuring the web interface.

Note

If you’re operating a single-node setup and would like to use HTTPS for the Graylog web interface and the Graylog REST API, it’s possible to use NGINX or Apache as a reverse proxy.

The last step is to enable Graylog during the operating system’s startup:

$ sudo chkconfig --add graylog-server
$ sudo systemctl daemon-reload
$ sudo systemctl enable graylog-server.service
$ sudo systemctl start graylog-server.service

The next step is to ingest messages into your Graylog and extract the messages with extractors or use the Pipelines to work with the messages.

SELinux information

Hint

We assume that you have policycoreutils-python installed to manage SELinux.

If you’re using SELinux on your system, you need to take care of the following settings:

  • Allow the web server to access the network: sudo setsebool -P httpd_can_network_connect 1

  • If the policy above does not comply with your security policy, you can also allow access to each port individually:
    • Graylog REST API and web interface: sudo semanage port -a -t http_port_t -p tcp 9000
    • Elasticsearch (only if the HTTP API is being used): sudo semanage port -a -t http_port_t -p tcp 9200
  • Allow using MongoDB’s default port (27017/tcp): sudo semanage port -a -t mongod_port_t -p tcp 27017

If you run a single server environment with NGINX or Apache proxy, enabling the Graylog REST API is enough. All other rules are only required in a multi-node setup.

Hint

Depending on your actual setup and configuration, you might need to add more SELinux rules to get to a running setup.

Multiple Server Setup

If you plan to have multiple server taking care of different roles in your cluster like we have in this big production setup you need to modify only a few settings. This is covered in our Multi-node Setup guide. The default file location guide will give you the file you need to modify in your setup.

Feedback

Please file a bug report in the GitHub repository for the operating system packages if you run into any packaging related issues.

If you found this documentation confusing or have more questions, please open an issue in the Github repository for the documentation.