Server composer install error: proc_open(): fork failed-Cannot allocate memory

After running these commands, the problem is resolved

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

Conclusion:
according to the problem description may be memory, maybe there is no give composer configuration memory?

ProgrammerAH