Netdata: Difference between revisions

Browse history interactively

← Older edit

VisualWikitext

@@ Line 1: / Line 1: @@
-Netdata will be part of the QualityBox dashboard.
+Netdata is one of the [https://discourse.equality-tech.com/t/dashboards-in-qualitybox/107 QualityBox dashboards].
-See http://wiki.freephile.org:20000/
+<!-- These services/entry points are disabled in production
-<!-- netdata.conf -->
+See [{{SERVER}}:20000/ this website Live]
+[{{SERVER}}:20000/netdata.conf Configuration]
+netdata.conf -->
 == System Locations ==
+Depending on how you install netdata, it will be distributed in the normal system locations such as
 <pre>
     - the daemon     at /usr/sbin/netdata
@@ Line 16: / Line 22: @@
     - logrotate file at /etc/logrotate.d/netdata
 </pre>
+Or, if you use
+<pre>bash <(curl -Ss https://my-netdata.io/kickstart-static64.sh)</pre>
+to install, you'll get all of netdata installed into <code>/opt/netdata</code>
+== With Ansible ==
+There is an [https://learn.netdata.cloud/docs/netdata-agent/installation/ansible Ansible Playbook for deploying Netdata Agent] across multiple nodes. At that page, they also describe how to disable the local dashboard by setting <code>web_mode</code> to none. The security configuration is described at https://learn.netdata.cloud/docs/netdata-agent/configuration/securing-agents/
 == Host Modifications ==
-Check KSM (kernel memory deduper)
+A Netdata role is available in [https://github.com/enterprisemediawiki/meza/blob/32.x/src/roles/netdata/tasks/main.yml the 32.x branch of Meza]
+Otherwise, you have to make room in HAProxy for netdata:
+=== HAProxy ===
+<syntaxhighlight lang="python">
+frontend netdata
+        bind *:20000 ssl crt /etc/haproxy/certs/wiki.freephile.org.pem
+        mode http
+        default_backend netdata-back
+backend netdata-back
+        server nd1 127.0.0.1:19999
+</syntaxhighlight>
+=== Kernel ===
+You have kernel memory de-duper (called [https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/virtualization_tuning_and_optimization_guide/chap-ksm Kernel Same-page Merging], or KSM) available, but it is not currently enabled.
 Memory de-duplication instructions
-You have kernel memory de-duper (called Kernel Same-page Merging,
-or KSM) available, but it is not currently enabled.
 To enable it run:
@@ Line 47: / Line 73: @@
 <code>systemctl start netdata</code>
-== Installation extras ==
+To reload configuration:
-The configuration will send messages to 'root' so be sure to either edit the conf <code>sudo vim /etc/netdata/health_alarm_notify.conf</code>, or set <code>vim /etc/aliases && newaliases</code>
+<code>killall -USR2 netdata</code> <ref>https://docs.netdata.cloud/health/quickstart/#reload-health-configuration</ref>
+== Notifications ==
+The default configuration will send messages to 'root' so be sure to either edit the conf <code>sudo vim /etc/netdata/health_alarm_notify.conf</code>, or set <code>vim /etc/aliases && newaliases</code>
+=== Turn off alarm ===
+<pre>
+     to: silent # silence notification; still see on website
+enabled: no     # disable alarm
+</pre>
+more details in the [https://docs.netdata.cloud/health/tutorials/stop-notifications-alarms/ netdata docs].
+== Issues ==
+You'll probably receive alarms for 'tcp listen drops'. This is likely bot-related (sending INVALID packets) and NOT due to your application dropping legitimate packets. There is a good discussion on how to identify the source of the problem and how to mitigate or resolve it [https://github.com/firehol/netdata/issues/3234 Issue #3234][https://github.com/firehol/netdata/issues/3826 Issue #3826] TLDR; increase the threshold to 1 (<code>/etc/netdata/health.d/tcp_listen.conf</code>) so you don't get bogus alerts.
+Also, you should modify your firewall to drop invalid packets before they're either counted (by netdata) or dropped (by the kernel).
+<syntaxhighlight lang="bash">
+iptables -A INPUT -m conntrack --ctstate INVALID -j DROP
+ip6tables -A INPUT -m conntrack --ctstate INVALID -j DROP
+iptables -A INPUT -m tcp -p tcp ! --tcp-flags FIN,SYN,RST,ACK SYN -m conntrack --ctstate NEW -j DROP
+ip6tables -A INPUT -m tcp -p tcp ! --tcp-flags FIN,SYN,RST,ACK SYN -m conntrack --ctstate NEW -j DROP
+</syntaxhighlight>
+Following the advice from NASA at https://wiki.earthdata.nasa.gov/display/HDD/SOMAXCONN, I increased my somaxconn kernel parameter to 1024 from 128
+<syntaxhighlight lang="bash">
+ cat /proc/sys/net/core/somaxconn
+ sysctl -w net.core.somaxconn=1024
+</syntaxhighlight>
+[[File:Tcp state diagram fixed.svg|600px|TCP State diagram]]
+== Updates ==
+Netdata will [https://github.com/firehol/netdata/wiki/Updating-Netdata update itself], and puts a script into cron:
+<code>
+ln -s /root/netdata/netdata-updater.sh /etc/cron.daily/netdata-updater
+</code>
+{{References}}
+[[Category:QualityBox]]
+[[Category:Monitoring]]