Encountering the error message “system has not been booted with systemd as init system (pid 1). can’t operate.” can be confusing, especially for users accustomed to systemd-based environments. This issue typically arises in specific scenarios where systemd is not the default init system, such as in Windows Subsystem for Linux (WSL) or Docker containers. In this guide, we’ll explore the causes of this error and provide effective solutions to manage your system effectively, whether you can enable systemd or need to work around its absence.
Understanding the Error
An init system is the first process started by the kernel during the booting process and is responsible for initializing the system. It manages system initialization, starts and stops services, and handles system shutdown. The init system plays a crucial role in ensuring that all necessary services and processes are up and running for the system to function correctly.
The Role of Systemd
Systemd is a popular init system used by many modern Linux distributions, including Ubuntu, Fedora, and Debian. It offers several advanced features, such as parallel service startup, on-demand starting of daemons, and dependency-based service control logic. These features contribute to faster boot times and more efficient resource management. Systemd also provides a unified interface for managing system services, logs, and configuration, making it a powerful tool for system administrators.
Common Scenarios for the Error
This error commonly occurs in environments where systemd is not the default init system. Two prevalent scenarios include:
- Windows Subsystem for Linux (WSL): WSL allows users to run a Linux environment directly on Windows without the overhead of a virtual machine. However, WSL traditionally uses a simpler init system rather than
systemd, which can lead to compatibility issues when running commands or services expectingsystemd. - Docker Containers: Docker containers are designed to be lightweight and often use minimal init systems to reduce overhead. As a result, they may not include
systemdby default, causing errors when trying to usesystemdspecific commands or configurations.
Checking Your Current Init System
Determining the init system in use is a straightforward process but crucial for effective system management and troubleshooting.
Using the ps Command
The ps command is a versatile tool for displaying information about active processes. To check your init system, execute the following command in the terminal:
ps -p 1 -o comm=This command outputs the name of the process with PID 1, which is the init system. If the output is systemd, it indicates that systemd is the active init system. If the output is init, it likely signifies that SysVinit is in use.
Using the symbolic link
The init system can also be identified by examining the symbolic link /sbin/init. Running the following command reveals the target of this link:
ls -l /sbin/initThe output will point to the executable managing the init process. For example:
systemdwill point to/lib/systemd/systemdSysVinitwill point to/sbin/init
Using the systemctl Command
If you suspect that systemd is in use, you can leverage systemctl, a systemd utility, to confirm:
systemctlIf systemd is active, this command will display a list of system services managed by systemd. If it is not installed or active, the command will fail, indicating that an alternative init system is in use.
How to Install and Enable Systemd in WSL
Enabling systemd in Linux Distro running on Windows Subsystem for Linux (WSL) involves several steps.
Pre-requisites
Before you begin, ensure the following:
WSL 2 Installed
Ensure you are running WSL 2, as it provides better compatibility with systemd due to its full Linux kernel.
wsl --list --verboseUpdated WSL and Ubuntu
Make sure both WSL and your Ubuntu distribution are up to date.
sudo apt update && sudo apt upgrade -yInstall Necessary Packages
Ensure your system has the latest updates and install systemd packages:
sudo apt install systemdModify WSL Configuration
To enable systemd in WSL (Windows Subsystem for Linux), you need to modify the WSL configuration file.
Open or create the WSL configuration file in your preferred text editor. Typically, this file is located at /etc/wsl.conf:
sudo nano /etc/wsl.confAdd the following lines to enable systemd:
[boot]
systemd=trueSave and exit the text editor.
Restart WSL
Restart your WSL instance to apply the changes. You can do this by shutting down WSL and then starting it again.
wsl --shutdown
wslAfter restarting, systemd should be active in your WSL environment.
Verifying Systemd Installation
To confirm that systemd is running as the init system, use the following command:
ps -p 1 -o comm=If the output is systemd, it indicates that systemd is successfully installed and running as PID 1.
Handling the Lack of Systemd
In environments where systemd cannot be enabled, such as some Docker containers or WSL instances, it’s essential to explore alternative methods for managing services and processes.
Service Management
Use service or rc-service (for OpenRC) to start, stop, and restart services.
sudo service <service-name> start
sudo service <service-name> stop
sudo service <service-name> restartScheduling Tasks
Replace systemd timers with cron jobs for scheduling recurring tasks.
crontab -eAdd a cron job in the format: * * * * /path/to/command
Running Services in WSL Without Systemd
When systemd isn’t available, managing services in WSL requires alternative methods. Let’s look at a practical example:
Starting Services Manually
You can start services manually using the service command:
sudo service apache2 start
sudo service mysql startCreating Custom Scripts
Automate service startup with a custom script. Create a file start-services.sh:
#!/bin/bash
sudo service apache2 start
sudo service mysql startMake the script executable and run it at startup:
chmod +x start-services.sh
./start-services.shUsing Cron for Automated Tasks
Schedule tasks with cron to ensure services start at boot. Edit the crontab:
crontab -eAdd a line to start services at reboot:
@reboot /path/to/start-services.shUsing Docker Without Systemd
In Docker environments, containers often lack systemd to keep them lightweight. Here’s how to manage services and processes effectively.
Supervisord
Use supervisord to manage processes within a container.
Install supervisor
sudo apt-get install supervisorStarting Supervisord
Start supervisord to launch and monitor services:
sudo supervisord -c /etc/supervisor/supervisord.confMonitoring and Control
Use supervisorctl to interact with running services:
sudo supervisorctl status
sudo supervisorctl start <service-name>
sudo supervisorctl stop <service-name>Docker Configuration Without Systemd
In Docker environments, it’s essential to manage services efficiently without systemd. Here’s how you can set up a multi-service container using supervisord:
Creating the Dockerfile
Use the following Dockerfile to install and configure supervisord:
FROM ubuntu:latest
RUN apt-get update && apt-get install -y supervisor nginx mysql-server
COPY supervisord.conf /etc/supervisor/conf.d/supervisord.conf
CMD ["/usr/bin/supervisord"]Supervisord Configuration
Create a supervisord.conf file to manage services:
[supervisord]
nodaemon=true
[program:nginx]
command=/usr/sbin/nginx -g "daemon off;"
autostart=true
autorestart=true
[program:mysql]
command=/usr/sbin/mysqld
autostart=true
autorestart=trueBuilding and Running the Docker Container
Build the Docker image and run the container:
docker build -t my-supervised-container .
docker run -d my-supervised-containerThis setup ensures that both Nginx and MySQL are managed and monitored by supervisord within the container, providing a robust alternative to systemd.
Conclusion
Handling the “system has not been booted with systemd as init system (pid 1)” error requires understanding the role of init systems and the environments where systemd is not the default. By identifying your current init system and adapting your approach, you can effectively manage services and processes whether or not systemd is available. With the steps provided, you can enable systemd in WSL or utilize alternatives in Docker, ensuring smooth and efficient system operations.
