WLS: Entropy setup on OL6.9 and 7.x (not UEK)

I was getting some hanging, clearly related to entropy while trying to upgrade an EMCC instance from 13.2 to 13.3.

The instructions below detail how to setup the entropy on Linux 6.9 and 7. This not is not applicable on UEK kernels that does not leverage this technology.

Linux 6.9

#1 Verify the entropy values

cat /proc/sys/kernel/random/entropy_avail

Recommended value should be higher than 1000

#2 Install rng

yum install rng-utils

#3 Start the rng process

# rngd -r /dev/urandom -o /dev/random -t 1

This command can be moved on /etc/rc.local

#4 Verify that the entropy is increased:

cat /proc/sys/kernel/random/entropy_avail

Linux 7

#1 Verify the entropy values

cat /proc/sys/kernel/random/entropy_avail

Recommended value should be higher than 1000

#2 Install rng

yum install rng-tools

#3 Configure rngd

echo "EXTRAOPTIONS=\"--rng-device=drng --no-tpm=1\"" >> /etc/sysconfig/rngd

#4 Update the kernel entries

sed -i-$(date '+%Y.%m.%d.%H%M%S') -e '/kernel.random.read_wakeup_threshold/d' -e '/kernel.random.write_wakeup_threshold/d' /etc/sysctl.conf
echo "kernel.random.read_wakeup_threshold = 2048" >> /etc/sysctl.conf
echo "kernel.random.write_wakeup_threshold = 3072" >> /etc/sysctl.conf

#5 Start the rng process

service rngd start
chkconfig rngd on

#6 Verify that the entropy is increased:

cat /proc/sys/kernel/random/entropy_avail