Redis logs `ERR Module failed to load: Permission denied` when it cannot access a module file due to restrictive file permissions, SELinux/AppArmor restrictions, or incorrect ownership. The module fails to initialize, leaving Redis without the expected functionality until you adjust permissions, disable security modules, or relocate the module file. This guide covers the symptoms, root causes, and ordered steps needed to successfully load Redis modules.
When Redis reports "ERR Module failed to load: Permission denied" it means the Redis server process lacks the necessary permissions to read, execute, or access the module file specified in the configuration. This error occurs during Redis startup or when dynamically loading modules via the `MODULE LOAD` command. The permission denial can stem from multiple layers: file system permissions (user/group ownership, read/execute bits), mandatory access control systems (SELinux on RHEL/CentOS, AppArmor on Ubuntu/Debian), or container/namespace restrictions when running Redis in Docker or Kubernetes. Redis treats module loading failures as fatal errors for that specific module, preventing its functionality from being available.
Verify the module file exists and examine its permissions and ownership:
# Locate the module file (common paths)
ls -la /usr/lib/redis/modules/
ls -la /opt/redis-stack/lib/
ls -la /path/to/your/module.so
# Check permissions and ownership
ls -l /path/to/module.so
stat -c "%n %U:%G %a" /path/to/module.so
# Verify Redis process user can access it
sudo -u redis ls -l /path/to/module.so
sudo -u redis test -r /path/to/module.so && echo "Readable"
sudo -u redis test -x /path/to/module.so && echo "Executable"The module file should be readable and executable by the Redis user (typically redis). If permissions are incorrect (e.g., 600), fix them with: sudo chmod 755 /path/to/module.so and sudo chown redis:redis /path/to/module.so.
Check if mandatory access control systems are blocking module access:
# For SELinux (RHEL/CentOS/Fedora)
sudo ausearch -m avc -ts recent | grep redis
sudo sealert -a /var/log/audit/audit.log
sudo semanage fcontext -l | grep redis
# For AppArmor (Ubuntu/Debian)
sudo aa-status | grep redis
sudo journalctl -u apparmor --since "1 hour ago" | grep -i deny
sudo cat /etc/apparmor.d/usr.sbin.redis-serverIf SELinux is blocking, you can temporarily test with sudo setenforce 0 (permissive mode) or create a proper policy. For AppArmor, add the module path to the Redis profile or run in complain mode: sudo aa-complain /usr/sbin/redis-server.
Check Redis configuration and attempt to load the module manually:
# Check redis.conf for module directives
grep -i module /etc/redis/redis.conf
# Try loading module manually via redis-cli
redis-cli MODULE LOAD /path/to/module.so
# Check loaded modules
redis-cli MODULE LIST
# If manual load works, add to configuration
echo "loadmodule /path/to/module.so" | sudo tee -a /etc/redis/redis.confIf manual loading fails with permission error but file permissions look correct, check filesystem mount options with mount | grep /path/to and ensure no noexec flag. Also verify Redis is running as the expected user: ps aux | grep redis-server.
If running Redis in Docker or Kubernetes, ensure proper volume mounts and permissions:
# Docker example with volume mount
docker run -d \
-v /host/path/modules:/usr/lib/redis/modules \
-v /host/path/redis.conf:/usr/local/etc/redis/redis.conf \
--user "1000:1000" \
redis:7.2 redis-server /usr/local/etc/redis/redis.conf
# Check container filesystem permissions
docker exec -it redis-container ls -la /usr/lib/redis/modules/
docker exec -it redis-container id
# Kubernetes pod security context example
securityContext:
runAsUser: 1000
runAsGroup: 1000
fsGroup: 1000Ensure the module file is mounted with correct ownership and that the container user has read/execute permissions. Consider using init containers to set proper permissions before Redis starts.
Redis modules are shared object (.so) files that must be compiled for the specific Redis version and architecture. Permission issues often mask deeper problems: the module might be compiled for a different glibc version, have missing dependencies (visible with ldd /path/to/module.so), or be corrupted. Always verify module integrity with file /path/to/module.so and strings /path/to/module.so | grep -i redis.
When using Redis Stack distributions, modules are typically pre-installed with correct permissions. Custom-compiled modules require careful attention to installation paths and Redis user permissions. In high-security environments, consider creating dedicated SELinux/AppArmor policies rather than disabling security features entirely.
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