Red Hat Installation with Self-Managed OpenSearch

The following article contains information on deploying Graylog with self-managed OpenSearch. Please note that Graylog Data Node is the preferred method of data management. See Get Started with Data Node for more information.

This guide describes the fastest way to install Graylog on Red Hat Enterprise Linux 7-9. All links and packages are present at the time of writing.

These installation steps also include installation of OpenSearch so that you can manage your search backend manually.

Warning: This guide does not cover security settings! The server administrator must make sure the Graylog server is not publicly exposed and is following security best practices.

Prerequisites

Hint: This guide assumes that any firewall is disabled and traffic can flow across all necessary ports.

Graylog 6.1 requires the following to maintain compatibility with its software dependencies:

Graylog Version	Minimum MongoDB Version	Maximum MongoDB Version	Minimum OpenSearch Version	Maximum OpenSearch Version
6.1.x	5.0.7	7.x	1.1.x (or 1.3.x for Graylog Security)	2.15.x

Warning: We caution you not to install or upgrade to OpenSearch 2.16! It is not supported. Doing so will break your instance!

Additionally, we recommend you review the version notes specific to your preferred version of Graylog for guidance on installing and configuring your Graylog instance.

Server Timezone

To set a specific time zone on the Graylog server, you can use the following command. (For more information on setting a time zone, we recommend this blog post.)

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sudo timedatectl set-timezone UTC

MongoDB

To install MongoDB on Red Hat, follow the tutorial for Red Hat from the MongoDB documentation.

First, add the repository file /etc/yum.repos.d/mongodb-org.repo with the following contents

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[mongodb-org-6.0]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/6.0/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-6.0.asc

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

Enable MongoDB during the operating system’s startup and verify it is running.

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sudo systemctl daemon-reload
sudo systemctl enable mongod
sudo systemctl start mongod
sudo systemctl status mongod

Hold the currently installed version of the MongoDB package to prevent it from being automatically upgraded to a newer version when updates are installed. sudo yum versionlock add mongodb-org
When you want to upgrade the package, be sure to remove the hold:
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```
sudo yum versionlock delete <package-name>
```
In the above code line, replace <package-name> with the correct package name.

OpenSearch

Hint: The remainder of this guide assumes that you wish to use Graylog with a self-managed OpenSearch deployment. Should you prefer to enable the Graylog Data Node, which is designed to configure and optimize OpenSearch for use with Graylog, please proceed now to Install Graylog Data Node.

Refer to the OpenSearch install page for detailed instructions.

The installation example below utilizes the YUM repository for installation.

1. Create a local repository file for OpenSearch.

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sudo curl -SL https://artifacts.opensearch.org/releases/bundle/opensearch/2.x/opensearch-2.x.repo -o /etc/yum.repos.d/opensearch-2.x.repo

2.Disable the YUM GPG check for the OpenSearch software package repository.

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sudo sed -i "s/^gpgcheck=.*/gpgcheck=0/g" /etc/yum.repos.d/opensearch-2.x.repo

3. Choose the version of OpenSearch you want to install. Unless otherwise indicated, the latest available version of OpenSearch is installed.

Hint: OpenSearch 2.12 and greater now requires setting the OPENSEARCH_INITIAL_ADMIN_PASSWORD environment variable when installing. The password must be a minimum of eight characters with at least one uppercase letter, one lowercase letter, one number, and one special character.

For example:

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sudo OPENSEARCH_INITIAL_ADMIN_PASSWORD=<custom-admin-password> yum -y install opensearch

To install a specific version of OpenSearch, specify the version manually using opensearch=<version>.

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sudo OPENSEARCH_INITIAL_ADMIN_PASSWORD=<custom-admin-password> yum -y install 'opensearch-2.15.0'

Warning: RHEL 9 may fail with a SHA-1 warning; please see the Red Hat documentation for guidance.

4. Hold the currently installed version of the OpenSearch package to prevent it from being automatically upgraded to a newer version when updates are installed.

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sudo yum versionlock add opensearch.x86_64-2.13

When you want to upgrade the package, be sure to remove the hold:

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sudo yum versionlock delete <package-name>

In the above code line, replace <package-name> with the correct package name.

Graylog Configuration for OpenSearch

1. Begin by opening the yml file.

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sudo nano /etc/opensearch/opensearch.yml

2. Update the following fields for a minimum unsecured running state (single node).

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cluster.name: graylog
node.name: ${HOSTNAME}
path.data: /var/lib/opensearch
path.logs: /var/log/opensearch
discovery.type: single-node
network.host: 0.0.0.0
action.auto_create_index: false
plugins.security.disabled: true
indices.query.bool.max_clause_count: 32768

3. Enable JVM options.

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sudo nano /etc/opensearch/jvm.options

4. Now, update the Xms and Xmx settings with half of the installed system memory, like shown in the example below.

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## JVM configuration
################################################################
## IMPORTANT: JVM heap size
################################################################
##
## You should always set the min and max JVM heap
## size to the same value. For example, to set
## the heap to 4 GB, set:
##
## -Xms4g
## -Xmx4g
##
## See https://opensearch.org/docs/opensearch/install/important-settings/
## for more information
##
################################################################
# Xms represents the initial size of total heap space
# Xmx represents the maximum size of total heap space
-Xms1g
-Xmx1g

5. Configure the kernel parameters at runtime.

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sudo sysctl -w vm.max_map_count=262144
echo 'vm.max_map_count=262144' | sudo tee -a /etc/sysctl.conf

6. Enable OpenSearch to start during operating system’s startup and verify it is running.

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sudo systemctl daemon-reload
sudo systemctl enable opensearch
sudo systemctl start opensearch
sudo systemctl status opensearch

Graylog

1. Install the Graylog repository configuration and Graylog Open itself with the following commands:

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sudo rpm -Uvh https://packages.graylog2.org/repo/packages/graylog-6.1-repository_latest.rpm
sudo yum install graylog-server

If you are installing Graylog Enterprise, then you will use the following commands:

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sudo rpm -Uvh https://packages.graylog2.org/repo/packages/graylog-6.1-repository_latest.rpm
sudo yum install graylog-enterprise

2. Mark the package on-hold so that package updates do not accidentally upgrade the Graylog server.

For Graylog Open:

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sudo yum versionlock add graylog-server-6.1

For Graylog Enterprise:

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sudo yum versionlock add graylog-enterprise-6.1

When you want to upgrade the package, be sure to remove the hold:

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sudo yum versionlock delete <package-name>

In the above code line, replace <package-name> with the correct package name.

Edit the Graylog Configuration File

1. Begin by opening the Graylog configuration file. Review the configuration file and edit as needed according to your preferences and environment.

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sudo nano /etc/graylog/server/server.conf

Warning: Add password_secret and root_password_sha2 values to the configuration file as these are mandatory and Graylog will not start without them.

2. To create your password_secret, run the following command:

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< /dev/urandom tr -dc A-Z-a-z-0-9 | head -c${1:-96};echo;

3. Use the following command to create your root_password_sha2:

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echo -n "Enter Password: " && head -1 </dev/stdin | tr -d '\n' | sha256sum | cut -d" " -f1

4. To be able to connect to Graylog, set the http_bind_address value in the configuration file to the public host name or a public IP address for the machine to which you can connect. More information about these settings can be found in Configuring the Web Interface. Alternatively, you can also set this configuration using this command:

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sudo sed -i 's/#http_bind_address = 127.0.0.1.*/http_bind_address = 0.0.0.0:9000/g' /etc/graylog/server/server.conf

Hint: 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.

5. Edit the elasticsearch_hosts setting to include a list of comma-separated URIs to one or more valid OpenSearch nodes. A sample specification may look as follows:

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elasticsearch_hosts = http://es-node-1.example.org:9200/foo,https://someuser:somepassword@es-node-2.example.org:9200

Warning: If this setting is not adjusted before start up, then you will NOT be able to log into Graylog using your previously configured root password!

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

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sudo systemctl daemon-reload
sudo systemctl enable graylog-server.service
sudo systemctl start graylog-server.service
sudo systemctl --type=service --state=active | grep graylog

Now you can ingest messages into Graylog!

Getting Started

Now that you have installed Graylog, you can review your initial configuration settings and connect to the web interface!

Cluster Setup

If you plan to have multiple servers assuming 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 lists the locations of the files you need to modify.

SELinux Information

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

If you’re using SELinux on your system, you must address 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. Having SELinux disabled during installation and enabling it later requires you to manually check the policies for MongoDB, OpenSearch, Elasticsearch, and Graylog.

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