How to Use Linux for System Resource Limitation and Control

How to use Linux to limit and control system resources

In Linux systems, we often need to limit and control system resources to ensure the stability and security of the system. This article will introduce how to use Linux's built-in resource control mechanism to limit and control the use of system resources. We will focus on two commonly used tools, cgroup (control group) and ulimit, as well as their usage examples.

1. cgroup

cgroup is a resource management mechanism provided by the Linux kernel. Through it, we can organize processes together and limit and control resources for these process groups. cgroups can control and limit the use of system resources such as CPU, memory, and I/O.

1. Install the cgroup tool

First, we need to install the cgroup tool. On most Linux distributions, it can be installed using the following command:

sudo apt-get install cgroup-tools

2. Create cgroup

We can use the cgcreate command to create a cgroup, for example, create a cgroup named For the cgroup of mygroup:

sudo cgcreate -g cpu,memory:mygroup

The above command creates a cgroup named mygroup and limits both CPU and memory on it.

3. Set cgroup resource limits

Next, we need to set cgroup resource limits. For example, we limit the CPU to use a maximum of 50% of the time slice, and limit the memory to use a maximum of 1GB of memory:

sudo cgset -r cpu.cfs_quota_us=50000 -r memory.limit_in_bytes=1G mygroup

The above command limits the CPU of mygroup to use a maximum of 50% of the time slice, and Limit memory usage to a maximum of 1GB of memory.

4. Add the process to cgroup

Finally, we can use the cgclassify command to add the process to the specified cgroup. For example, add the process with process PID 12345 to mygroup:

sudo cgclassify -g cpu,memory:mygroup 12345

Now, the process with process PID 12345 will be subject to the resource restrictions of mygroup.

2. ulimit

In addition to cgroup, Linux also provides another powerful resource control tool ulimit. ulimit allows us to limit the system resources that a single user can use.

1. View current resource limits

We can use the ulimit command to view the current resource limit settings. For example, to view the maximum file size limit that the current user can use:

ulimit -f

2. Set resource limits

We can use the ulimit command to set resource limits. For example, to set the maximum file size limit to 1GB:

ulimit -f 1000000000

The above command sets the maximum file size limit to 1GB.

In addition, we can also use the ulimit command to set other resource limits, such as CPU time, memory, number of open files, etc.

3. Permanently modify resource limits

The resource limits set through the ulimit command are only valid for the current session. Once the session ends, the settings will become invalid. If we want to permanently modify resource limits, we can modify the system configuration file /etc/security/limits.conf.

For example, if you want to change the maximum number of open files to 10000, you can add the following configuration to /etc/security/limits.conf:

*    hard    nofile    10000

The above configuration will change the maximum number of open files The limit is modified to 10000.

Conclusion

This article introduces how to use Linux for system resource limitation and control. We focused on two commonly used tools, cgroup and ulimit, and gave corresponding usage examples. By using these tools rationally, we can effectively control the use of system resources and ensure the stability and security of the system. I hope this article will be helpful to readers who use Linux to limit and control system resources.

References:

• https://www.man7.org/linux/man-pages/man7/cgroups.7.html
• https:/ /www.man7.org/linux/man-pages/man2/setrlimit.2.html
• https://linux.die.net/man/1/ulimit

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