Many website owners face the error “proc_open(): fork failed – Cannot allocate memory” while installing PHP frameworks or packages.

Most of the PHP frameworks use “composer” as the dependency management tool, which throws this error during insufficient memory and improper swap space allocation.

At Bobcares, we often resolve similar support requests from webmasters, web hosts, and other online service providers as part of our Server Management Services.

Read more to know what causes this error and what we can do to prevent it in the future.

Why this proc_open() fork failed error occur?

PHP framework like Laravel works with the help of Composer. It is a major dependency on creating Laravel projects. Because it declares the libraries needed for the project.

We can install all the new packages required for the  application using the command:

composer install

In order to add any new package to the application, we use the command:

composer require <package>

But running this command sometimes ends up in errors.

One such error is “proc_open(): fork failed – Cannot allocate memory”.

The main reasons for this error to occur are insufficient memory and improper swap space allocation.

Let’s see how to fix it.

What is the fix for proc_open() fork failed error?

When this error appears, the first thing to check is the available memory in the server. To find it out, use the command:

free -m

The result provides details like total, used, and free spaces in the server. Also, this provides data regarding available swap space in the server.

The error appears while installing new packages if there is no free space available.

In such scenarios, we ask customers to add more memory for fixing the error.

However, there are cases where this error appears even if there is enough space.

In such a case, we check the allocated swap space in the server.

Because, if there is no free swap space, some installation could not be completed and end up showing this error.

We use the commands below for enabling the swap space in such a scenario.

/bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=1024
/sbin/mkswap /var/swap.1
/sbin/swapon /var/swap.1

This fixes the error.

[Need assistance in fixing composer errors? Click here to talk to our experts.]

Conclusion

In short, we discussed in detail that the main reasons for proc_open() fork failed error to occur are insufficient memory and improper swap space allocation. We also discussed how our Support Engineers fix this error easily.