First, you need to download the file using Wget and then install it using RPM on your system to enable the EPEL repository.

RHEL/CentOS 7 64 Bit

# wget http://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
# rpm -ivh epel-release-latest-7.noarch.rpm

## RHEL/CentOS 6 64-Bit ##

# wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
# rpm -ivh epel-release-6-8.noarch.rpm

Check the installation

# yum repolist
*epel/x86_64 Extra Packages for Enterprise Linux 7 - x86_64

Now, install stress

# yum install stress

To test, first run the uptime command and note down the load average. Next, run the stress command to spawn 8 workers spinning on sqrt() with a timeout of 20 seconds. After running stress, again run the uptime command and compare the load average.

# uptime
16:39:03 up 1 day, 18:32,  1 user,  load average: 0.15, 0.24, 0.14

sudo stress --cpu  8 --timeout 20
stress: info: [65429] dispatching hogs: 8 cpu, 0 io, 0 vm, 0 hdd
stress: info: [65429] successful run completed in 20s

Now uptime again

# uptime
 16:40:18 up 1 day, 18:34,  1 user,  load average: 1.35, 0.59, 0.27

Spawn 8 workers spinning on sqrt() with a timeout of 30 seconds

]# uptime
16:41:52 up 1 day, 18:35, 1 user, load average: 0.28, 0.43, 0.24
[root@server rogerp]# sudo stress –cpu 8 -v –timeout 30s
stress: info: [65654] dispatching hogs: 8 cpu, 0 io, 0 vm, 0 hdd
stress: dbug: [65654] using backoff sleep of 24000us
stress: dbug: [65654] setting timeout to 30s
stress: dbug: [65654] –> hogcpu worker 8 [65655] forked
stress: dbug: [65654] using backoff sleep of 21000us
stress: dbug: [65654] setting timeout to 30s
stress: dbug: [65654] –> hogcpu worker 7 [65656] forked
stress: dbug: [65654] using backoff sleep of 18000us
stress: dbug: [65654] setting timeout to 30s
stress: dbug: [65654] –> hogcpu worker 6 [65657] forked
stress: dbug: [65654] using backoff sleep of 15000us
stress: dbug: [65654] setting timeout to 30s
stress: dbug: [65654] –> hogcpu worker 5 [65658] forked
stress: dbug: [65654] using backoff sleep of 12000us
stress: dbug: [65654] setting timeout to 30s
stress: dbug: [65654] –> hogcpu worker 4 [65659] forked
stress: dbug: [65654] using backoff sleep of 9000us
stress: dbug: [65654] setting timeout to 30s
stress: dbug: [65654] –> hogcpu worker 3 [65660] forked
stress: dbug: [65654] using backoff sleep of 6000us
stress: dbug: [65654] setting timeout to 30s
stress: dbug: [65654] –> hogcpu worker 2 [65661] forked
stress: dbug: [65654] using backoff sleep of 3000us
stress: dbug: [65654] setting timeout to 30s
stress: dbug: [65654] –> hogcpu worker 1 [65662] forked
stress: dbug: [65654] <-- worker 65659 signalled normally stress: dbug: [65654] <-- worker 65658 signalled normally stress: dbug: [65654] <-- worker 65660 signalled normally stress: dbug: [65654] <-- worker 65656 signalled normally stress: dbug: [65654] <-- worker 65655 signalled normally stress: dbug: [65654] <-- worker 65657 signalled normally stress: dbug: [65654] <-- worker 65662 signalled normally stress: dbug: [65654] <-- worker 65661 signalled normally stress: info: [65654] successful run completed in 30s [root@server rogerp]# uptime 16:43:10 up 1 day, 18:37, 1 user, load average: 1.87, 1.06, 0.49 [/bash]