Difference between revisions of "OS/Entropy"

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  cat /proc/sys/kernel/random/entropy_avail
 
  cat /proc/sys/kernel/random/entropy_avail
  
If necessary, install rng tools and start, then recheck entropy
+
If necessary (available < 1000), install rng tools and start, then recheck entropy
 
  yum -y install rng-tools
 
  yum -y install rng-tools
 
  systemctl start rngd
 
  systemctl start rngd
Line 14: Line 14:
 
  rngd.service - Hardware RNG Entropy Gatherer Daemon
 
  rngd.service - Hardware RNG Entropy Gatherer Daemon
 
   Loaded: loaded (/usr/lib/systemd/system/rngd.service; enabled; vendor preset: enabled)
 
   Loaded: loaded (/usr/lib/systemd/system/rngd.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Wed 2016-11-09 09:40:02 GMT; 1min 23s ago
+
   Active: '''failed''' (Result: exit-code) since Wed 2016-11-09 09:40:02 GMT; 1min 23s ago
 
  Main PID: 12778 (code=exited, status=1/FAILURE)
 
  Main PID: 12778 (code=exited, status=1/FAILURE)
 +
 +
Edit the service  unit file: /usr/lib/systemd/system/rngd.service.
 +
The ExecStart line should be edited so that it reads as in the following:
 +
ExecStart=/sbin/rngd -f -r /dev/urandom
 +
 +
Now, restart and check the the service
 +
systemctl daemon-reload
 +
systemctl start rngd
 +
systemctl status rngd
 +
 +
Output should look similar to the following:
 +
â rngd.service - Hardware RNG Entropy Gatherer Daemon
 +
  Loaded: loaded (/usr/lib/systemd/system/rngd.service; enabled; vendor preset: enabled)
 +
  Active: '''active''' (running) since Wed 2016-11-09 09:44:14 GMT; 2s ago
 +
Main PID: 12858 (rngd)
 +
  CGroup: /system.slice/rngd.service
 +
          ââ12858 /sbin/rngd -f -r /dev/urandom
 +
 +
Recheck the available entropy (should be > 1000)

Latest revision as of 09:45, 9 November 2016

Check Entropy Figure

cat /proc/sys/kernel/random/entropy_avail

If necessary (available < 1000), install rng tools and start, then recheck entropy

yum -y install rng-tools
systemctl start rngd
systemctl enable rngd


Check the status of rngd

 systemctl status rngd

If you see a failure

rngd.service - Hardware RNG Entropy Gatherer Daemon
  Loaded: loaded (/usr/lib/systemd/system/rngd.service; enabled; vendor preset: enabled)
  Active: failed (Result: exit-code) since Wed 2016-11-09 09:40:02 GMT; 1min 23s ago
Main PID: 12778 (code=exited, status=1/FAILURE)

Edit the service unit file: /usr/lib/systemd/system/rngd.service. The ExecStart line should be edited so that it reads as in the following:

ExecStart=/sbin/rngd -f -r /dev/urandom

Now, restart and check the the service

systemctl daemon-reload
systemctl start rngd
systemctl status rngd

Output should look similar to the following: â rngd.service - Hardware RNG Entropy Gatherer Daemon

  Loaded: loaded (/usr/lib/systemd/system/rngd.service; enabled; vendor preset: enabled)
  Active: active (running) since Wed 2016-11-09 09:44:14 GMT; 2s ago
Main PID: 12858 (rngd)
  CGroup: /system.slice/rngd.service
          ââ12858 /sbin/rngd -f -r /dev/urandom

Recheck the available entropy (should be > 1000)