Linux systemd Dependency Failed — Service Cannot Start

Overview

A systemd service failing due to dependency means a required service it depends on has not started or has failed.

Key Details

• systemd services can declare dependencies with Requires=, Wants=, After=
• If a Required dependency fails, the dependent service also fails
• Wants= dependencies are softer — the service starts even if they fail
• Circular dependencies can prevent entire dependency chains from starting
• systemd orders startup based on Before= and After= directives

Common Causes

• Required dependency service failed to start
• Circular dependency between two or more services
• Network-dependent service started before network was ready
• Mount point dependency not available at service start time
• Custom service missing After=network-online.target directive

Steps

1. 1Check which dependency failed: systemctl status service-name — look for 'dependency failed'
2. 2List dependencies: systemctl list-dependencies service-name
3. 3Fix the failed dependency first, then restart the dependent service
4. 4For network services, add After=network-online.target and Wants=network-online.target
5. 5Check for circular deps: systemd-analyze verify /etc/systemd/system/service-name.service

Tags

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Frequently Asked Questions