Month: April 2019

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EVA ICS on Ubuntu: copy/paste install

This article describes, how to install EVA ICS on Ubuntu or Debian. Actually it duplicates the information from EVA ICS installation docs, however is focused on Ubuntu with local mosquitto MQTT server, has minimal description and contains all required commands which could be just copy/pasted in console shell.

So let’s consider you have fresh Ubuntu install (I’ve used 18.04 LTS). What should be done, before we can launch EVA ICS easy-setup:

  • Install required OS packages
  • Configure local mosquitto MQTT server
  • Configure EVA ICS venv to skip building “heavy” numpy/pandas modules (we’ll use them from OS repository)

Let’s go.

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Tips and tricks with EVA CLI

Primary EVA CLI tools are eva (./bin/eva) and eva-shell (./bin/eva -I or ./bin/eva-shell). Actually it’s a same program, which automatically starts itself in interactive mode (-I) when called as eva-shell and without any argument.

Interactive mode

If command “uc”, “lm” or “sfa” is called without arguments, EVA shell will launch corresponding controller sub-shell, which’s equal to calling uc-cmd, lm-cmd and sfa-cmd directly.

You can execute a pack of several commands at once, separating them with “;” symbol, just like in a system shell:

state -p sensor ; state -p unit

The next very useful trick is command repeating. In real life, there’s a lot of examples, when you mount / setup some equipment and need to check its state every second to get the moment it start working correctly. To repeat the command
in EVA shell , symbol “|” (pipe) is used

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Threads in EVA ICS

EVA ICS doesn’t use thread pools in core, number of threads is always fixed (except LM PLC macros), grows together with node configuration, and should be controlled by system administrator/integrator. Majority threads “sleep” until they get an event and don’t produce additional load.

After controller start, core launches several system threads (garbage collectors etc.), plus threads for each item:

  • Two update threads (update scheduler + update processor) per each unit, sensor and lvar
  • One action thread per each unit
  • Two update threads for PHI module, if loaded with update=X parameter
  • One notification queue thread for each notifier
  • One thread for UC UDP API, one thread for UC SNMP trap handler (if enabled).
  • LM PLC launches a single thread which handles queue for scheduled macro exections. After the execution, each macro has its own thread, number of threads for macros isn’t limited by PLC.
  • Also, each LM PLC logic cycle has own thread as well
  • If MQTT transport is used for API calls between nodes – one thread per API call (max lifetime = server.timeout)
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Welcome to EVA ICS blog!

In this blog we’ll explain how EVA ICS works, write articles with examples and real-life usage cases and discuss various general automation tips, tricks and problems.