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Posted to commits@brooklyn.apache.org by dr...@apache.org on 2016/12/13 17:51:12 UTC
[1/2] brooklyn-docs git commit: Increasing entropy for RHEL 7
Repository: brooklyn-docs
Updated Branches:
refs/heads/master 2c002ce69 -> 84f1fe282
Increasing entropy for RHEL 7
Project: http://git-wip-us.apache.org/repos/asf/brooklyn-docs/repo
Commit: http://git-wip-us.apache.org/repos/asf/brooklyn-docs/commit/6dab0b0c
Tree: http://git-wip-us.apache.org/repos/asf/brooklyn-docs/tree/6dab0b0c
Diff: http://git-wip-us.apache.org/repos/asf/brooklyn-docs/diff/6dab0b0c
Branch: refs/heads/master
Commit: 6dab0b0c204a0209efbb57899f4e5c186d55c2d3
Parents: 2c002ce
Author: Valentin Aitken <bo...@gmail.com>
Authored: Mon Dec 5 23:01:49 2016 +0200
Committer: Valentin Aitken <bo...@gmail.com>
Committed: Fri Dec 9 19:29:01 2016 +0200
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guide/ops/troubleshooting/increase-entropy.md | 39 +++++++++++++++++++---
1 file changed, 34 insertions(+), 5 deletions(-)
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http://git-wip-us.apache.org/repos/asf/brooklyn-docs/blob/6dab0b0c/guide/ops/troubleshooting/increase-entropy.md
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diff --git a/guide/ops/troubleshooting/increase-entropy.md b/guide/ops/troubleshooting/increase-entropy.md
index a6b5872..886adef 100644
--- a/guide/ops/troubleshooting/increase-entropy.md
+++ b/guide/ops/troubleshooting/increase-entropy.md
@@ -4,24 +4,52 @@ title: Increase Entropy
toc: /guide/toc.json
---
-If you are installing Apache Brooklyn on a virtual machine, you may find it useful to increase the
-Linux kernel entropy to speed up the ssh connections to the managed entities. You can install and
-configure `rng-tools` or just use /dev/urandom`.
+### Checking entropy level
+
+A lack of entropy can cause random number generation to be extremely slow.
+This results in tasks like ssh to also be extremely slow.
+One can check the available entropy on a machine by running the command:
+
+{% highlight bash %}
+cat /proc/sys/kernel/random/entropy_avail
+{% endhighlight %}
+
+It should be a value above 2000.
+
+If you are installing Apache Brooklyn on a virtual machine, you may find that it has insufficient
+entropy. You may need to increase the Linux kernel entropy in order to speed up the ssh connections
+to the managed entities. You can install and configure `rng-tools`, or just use /dev/urandom`.
### Installing rng-tool
-if you are using a RHEL-based OS:
+If you are using a RHEL 6 based OS:
{% highlight bash %}
+sudo -i
yum -y -q install rng-tools
echo "EXTRAOPTIONS=\"-r /dev/urandom\"" | cat >> /etc/sysconfig/rngd
/etc/init.d/rngd start
{% endhighlight %}
-if you are using a Debian-based OS:
+If you are using a RHEL 7 or a systemd based system:
+
+{% highlight bash %}
+sudo yum -y -q install rng-tools
+
+# Configure rng to use /dev/urandom
+# Change the "ExecStart" line to:
+# ExecStart=/sbin/rngd -f -r /dev/urandom
+sudo vi /etc/systemd/system/multi-user.target.wants/rngd.service
+
+sudo systemctl daemon-reload
+sudo systemctl start rngd
+{% endhighlight %}
+
+If you are using a Debian-based OS:
{% highlight bash %}
+sudo -i
apt-get -y install rng-tools
echo "HRNGDEVICE=/dev/urandom" | cat >> /etc/default/rng-tools
/etc/init.d/rng-tools start
@@ -40,3 +68,4 @@ sudo mv /dev/random /dev/random-real
sudo ln -s /dev/urandom /dev/random
{% endhighlight %}
+Notice! If you map /dev/random to use /dev/urandom you will need to restart the Apache Brooklyn java process in order for the change to take place.
[2/2] brooklyn-docs git commit: This closes #131
Posted by dr...@apache.org.
This closes #131
Project: http://git-wip-us.apache.org/repos/asf/brooklyn-docs/repo
Commit: http://git-wip-us.apache.org/repos/asf/brooklyn-docs/commit/84f1fe28
Tree: http://git-wip-us.apache.org/repos/asf/brooklyn-docs/tree/84f1fe28
Diff: http://git-wip-us.apache.org/repos/asf/brooklyn-docs/diff/84f1fe28
Branch: refs/heads/master
Commit: 84f1fe2823217df7e1d2a15d6f76a4b4af846aa1
Parents: 2c002ce 6dab0b0
Author: Duncan Godwin <dr...@googlemail.com>
Authored: Tue Dec 13 17:48:53 2016 +0000
Committer: Duncan Godwin <dr...@googlemail.com>
Committed: Tue Dec 13 17:48:53 2016 +0000
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guide/ops/troubleshooting/increase-entropy.md | 39 +++++++++++++++++++---
1 file changed, 34 insertions(+), 5 deletions(-)
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