Service Management
In RHEL, you can manage services using systemctl, which allows you to start, stop, restart, enable, and check the status of systemd services. Additionally, you can find and manage running processes using their Process ID (PID) with commands like ps aux, pgrep <service-name>, or kill <PID> for manual control over service-related processes.
RHEL Service Administration
systemctl is a command-line tool used to manage systemd services on Linux, allowing you to start, stop, restart, enable, and disable services. It also provides status information, logs, and dependency management for system services and targets.
You can view a process ID (PID) and its resource usage using ps aux or top, which display CPU, memory, and other details. For a real-time view, htop provides an interactive interface to monitor and manage processes efficiently.
You can view service logs using journalctl -u <service-name>, which displays logs for a specific systemd service. For real-time monitoring, use journalctl -fu <service-name> to continuously stream new log entries.
htop is an interactive process viewer for Linux that provides a real-time, color-coded display of system resource usage, including CPU, memory, and running processes. It offers an intuitive interface with sorting, filtering, and process management features, making it a more user-friendly alternative to top.
systemclt Commands
View Service Details
systemctl status firewalld
Manage Services
Start a Service
Stop a Service
Soft Kill by Process ID
Hard Kill by Process ID
sudo systemctl start firewalld
sudo systemctl start firewalld
sudo kill 888
sudo kill -9 888
Service Dependancies
systemctl show NetworkManager.service | grep -E 'Requires=|After=|Wants='
You can then query the required services to see if they are running...
ViewServices
systemctl --type=service --state=running | sort
PS
Check Process Memory Usage (KB):
ps -eo pid,user,s,comm,size,vsize,rss --sort -size | head -1; ps -eo pid,user,s,comm,size,vsize,rss --sort -size | grep firewalld
Check Process Usage:
ps aux | head -1; ps aux | grep 888
htop
Viewing with htop
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Enable Required Repositories:
sudo subscription-manager repos --enable codeready-builder-for-rhel-9-$(arch)-rpms
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Install EPEL:
sudo dnf install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm
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Install htop
sudo dnf install -y htop
just run the command htop
journalctl
You can see the logs for specific service. These are great for troubleshooting.
sudo journalctl -u NetworkManager.service
