Control Kong Gateway through systemd

This document includes instructions on how to integrate Kong Gateway with systemd for Debian and RPM based packages.

Note that some of the supported GNU/Linux distributions for Kong Gateway may not have adopted systemd as their default init system (for example, CentOS 6 and RHEL 6). For the following instructions, it is assumed that Kong Gateway has already been installed and configured on a systemd-supported GNU/Linux distribution.

systemd commands for working with Kong Gateway

Start Kong Gateway

# For Kong Gateway
sudo systemctl start kong-enterprise-edition

# For Kong Gateway (OSS)
sudo systemctl start kong

Stop Kong Gateway

# For Kong Gateway
sudo systemctl stop kong-enterprise-edition

# For Kong Gateway (OSS)
sudo systemctl stop kong

Start Kong Gateway at system boot

Enable starting Kong Gateway automatically at system boot

# For Kong Gateway
sudo systemctl enable kong-enterprise-edition

# For Kong Gateway (OSS)
sudo systemctl enable kong

Disable starting Kong Gateway automatically at system boot

# For Kong Gateway
sudo systemctl disable kong-enterprise-edition

# For Kong Gateway (OSS)
sudo systemctl disable kong

Restart Kong Gateway

# For Kong Gateway
sudo systemctl restart kong-enterprise-edition

# For Kong Gateway (OSS)
sudo systemctl restart kong

Query Kong Gateway status

# For Kong Gateway
sudo systemctl status kong-enterprise-edition

# For Kong Gateway (OSS)
sudo systemctl status kong

Customize the Kong Gateway unit file

The official systemd service is located at /lib/systemd/system/kong-enterprise-edition.service for Kong Gateway, or at /lib/systemd/system/kong.service for Kong Gateway (OSS).

Note that the official Kong systemd service doesn’t set user or group as root, which is required to run the system file. See the example below with both user and group both set to root:

[Unit]
Description=Kong Gateway
Documentation=https://docs.konghq.com/gateway/
After=syslog.target network.target remote-fs.target nss-lookup.target
[Service]
User=root
Group=root
ExecStartPre=/usr/local/bin/kong prepare -p /usr/local/kong -c /home/ec2-user/kong.conf
ExecStart=/usr/local/openresty/nginx/sbin/nginx -p /usr/local/kong -c nginx.conf
ExecReload=/usr/local/bin/kong prepare -p /usr/local/kong
ExecReload=/usr/local/openresty/nginx/sbin/nginx -p /usr/local/kong -c nginx.conf -s reload
ExecStop=/bin/kill -s QUIT $MAINPID
PrivateTmp=true
# All environment variables prefixed with KONG_ and capitalized will override
# the settings specified in the /etc/kong/kong.conf.default file.
#
# For example:
#   log_level = debug in the .conf file -> KONG_LOG_LEVEL=debug env var.
Environment=KONG_NGINX_DAEMON=off
# You can control this limit through /etc/security/limits.conf
LimitNOFILE=infinity
[Install]
WantedBy=multi-user.target

For scenarios where customizations are needed (for example, configuring Kong or modifying the service file behavior), we recommend creating another service at /etc/systemd/system/kong-enterprise-edition.service for Kong Gateway, or at /etc/systemd/system/kong.service for Kong Gateway (OSS), to avoid conflicts upon reinstalling or upgrading Kong.

All environment variables prefixed with KONG_ and capitalized will override the settings specified in the /etc/kong/kong.conf.default file. For example: log_level = debug in the .conf file translates to the KONG_LOG_LEVEL=debug environment variable.

You can also choose use a configuration file instead of environment variables. In this case, modify the ExecStartPre systemd directive to execute kong prepare with the -c argument to point to your configuration file. For example, if you have a custom configuration file at /etc/kong/kong.conf, modify the ExecStartPre directive as follows:

ExecStartPre=/usr/local/bin/kong prepare -p /usr/local/kong -c /etc/kong/kong.conf

When linking non environment files using the EnvironmentFile systemd directive, note that the systemd parser will only recognize environment variables assignments. For example, if one of the Kong’s default configuration files are linked (/etc/kong/kong.conf.default and /etc/kong.conf), non environment variables assignments in the file could lead to systemd errors. In this case, systemd will not allow the Kong service to be started. For this reason, we recommend specifying an EnvironmentFile other than the default ones:

EnvironmentFile=/etc/kong/kong_env.conf

Logging to syslog and journald

In this case, adding the below Environment systemd directives to your customized systemd service file at /etc/systemd/system/kong-enterprise-edition.service will do it:

Environment=KONG_PROXY_ACCESS_LOG=syslog:server=unix:/dev/log
Environment=KONG_PROXY_ERROR_LOG=syslog:server=unix:/dev/log
Environment=KONG_ADMIN_ACCESS_LOG=syslog:server=unix:/dev/log
Environment=KONG_ADMIN_ERROR_LOG=syslog:server=unix:/dev/log

To view the journald logs:

# For Kong Gateway
journalctl -u kong-enterprise-edition

# For Kong Gateway (OSS)
journalctl -u kong

To view the syslog logs:

tail -F /var/log/syslog

Customize Kong’s Nginx instance using the Nginx directive injection system

To use the injection system with environment variables, add the below Environment systemd directive to your custom service at /etc/systemd/system/kong-enterprise-edition.service (Kong Gateway) or /etc/systemd/system/kong.service (Kong Gateway (OSS)). Note the quoting rules defined by systemd to specify an environment variable containing spaces:

Environment="KONG_NGINX_HTTP_OUTPUT_BUFFERS=4 64k"

Customize Kong’s Nginx instance using ––nginx-conf

To use the --nginx-conf argument, modify the ExecStartPre systemd directive to execute kong prepare with the --nginx-conf argument. For example, if you have a custom template at /usr/local/kong/custom-nginx.template, modify the ExecStartPre directive as follows:

ExecStartPre=/usr/local/bin/kong prepare -p /usr/local/kong --nginx-conf /usr/local/kong/custom-nginx.template

Customize Kong’s Nginx instance including files via the injected Nginx directives

To include files via the injected Nginx directives with environment variables, add the below Environment systemd directive to your custom service at /etc/systemd/system/kong-enterprise-edition.service (Kong Gateway) or /etc/systemd/system/kong.service (Kong Gateway (OSS)):

Environment=KONG_NGINX_HTTP_INCLUDE=/path/to/your/my-server.kong.conf