ISA¶

Example¶

In this section, an example is given with many flags. If some flags are not clear, these can be looked up in the Arguments section of this document.

isa nodes.ini --out results.csv -f -p collectl -t 5 -i 10 --interlogin 3 --max-nodes 2

This snippet reads the nodes.ini file for node configuration. Results are written to results.csv and since it ends on .csv, the output type is automatically set to csv. The -f flag makes sure to force the recreation of the output file even if the file already exists. The collectl plugin is used for gathering node information. The timeout is set to 5 seconds (-t 5), so nodes try to login for at most 5 seconds. The interval time is set to 10 seconds (-i 10), which makes sure that information is gathered every 10 seconds. The interlogin time is set to 3 seconds, so between consecutive logins of groups of 2 nodes (specified by –max-nodes 2) the script will wait 3 seconds (–interlogin 3). Notice that a mixture of shortcut arguments and normal arguments is used. It is up to you what you prefer.

Debugging¶

If there is not enough information visible, you can add the -v flag for seeing INFO logs (this is also the default if no -v or -vv flag is present). If this is still not enough, you can use the -vv flag (which stands for Very Verbose) to see DEBUG logs and INFO logs. This is illustrated by the following example:

isa nodes.ini --vv

Arguments¶

isa nodes.ini --output results.csv
isa nodes.ini -o results.csv

isa nodes.ini --out output.csv --output-type csv

isa nodes.ini --out output.csv --force

isa nodes.ini --interlogin 1 --max-nodes 5

isa nodes.ini --plugins iostat,myplugin

isa nodes.ini --timeout 10

isa nodes.ini --interval 5

isa nodes.ini --interlogin 1

isa nodes.ini --interlogin 1 --max-nodes 5

isa nodes.ini --skip-install

isa nodes.ini -vv

Minimal example¶

[node1]
host = 127.0.0.1
enabled = False

[node2]
host = 127.0.0.2
port = 23

In this simplified example, there are two nodes. One of the nodes (node1) is disabled and will not be monitored. By default, nodes are enabled, so node2 will be monitored. Furthermore, the host (which can be either an hostname or IP address) of node1 is 127.0.0.1 and the host of node2 is 127.0.0.2. The port of node2 is 23. Looking at the structure of the example, each section corresponds to a unique node name and every section contains flags which can be set. Some flags are optional and other flags are required.

Flags¶

This section explains all flags that can be used within a node section.

[node1]
host = 127.0.0.1
via = login

[node2]
host = 127.0.0.2
via = login

[login]
host = 127.0.0.3

List of build-in plugins¶

Creating a plugin¶

A plugin file is named as follows: plugin_pluginname.py. Then, you can call ISA with a list of plugins and you can add pluginname to the comma separated list of the plugins argument of ISA. It is very easy to create a new plugin. The plugin script should have the following structure:

def plugin_init(args):
   return MyPlugin(...)

class MyPlugin(Plugin):
   def install(self, server):
      server.execute(...)
   def collect(self, server):
      server.execute(...)

You see a collect method and a install method. The install method is called once after logging in to all the servers and its aim is to install software when it is not installed yet on the server. The collect method is used for collecting statistics on the server. The install method is not required! If you use the install method for installing a package, you can use the install_package method from the Plugin class. This is demonstrated in the next example:

def plugin_init(args):
   return MyPlugin(...)

class MyPlugin(Plugin):
   def install(self, server):
      self.install_package(server, 'sysstat')
   def collect(self, server):
      server.execute(...)

This example tries to install sysstat using different package managers (like yum and apt-get).

It is also possible to leave out the install method as is shown in the next example:

def plugin_init(args):
   return MyPlugin(...)

class MyPlugin(Plugin):
   def collect(self, server):
      server.execute(...)

The plugin is first initialized. You can use arguments from the original ISA call. For example, suppose ISA is called as follows:

isa nodes.ini --timeout 3

Then you can use args.timeout to refer to the timeout argument:

def plugin_init(args):
   return MyPlugin(args.timeout)

class MyPlugin(Plugin):
   def install(self, server):
      print("I assume my monitoring software is already installed on the server.")

   def __init__(self, timeout):
      print("I am called with timeout=%s" % timeout)

   def collect(self, server):
      server.execute(...)

The collect method should return either a list of dictionaries or a dictionary which specifies the collected data in key-value pairs:

def plugin_init(args):
   return MyPlugin()

class MyPlugin(Plugin):
   def install(self, server):
      pass

   def collect(self, server):
      return {
         'temperature': 25.0
      }

Or you can use a list:

def plugin_init(args):
   return MyPlugin()

class MyPlugin(Plugin):
   def install(self, server):
      pass

   def collect(self, server):
      return [{
         'sensor': 'A',
         'temperature': 15.0
      }, {
         'sensor': 'B',
         'temperature': 35.0
      }]

Version 1.2.4¶

• Fixed double argument character bug

Version 1.2.3¶

• Feature: skip installation
• Bugfixing

Version 1.2.2¶

• Test fixing

Version 1.2.1¶

• Version change

Version 1.2.0¶

• Version change

Version 1.1.10¶

• New flags: output-type, force and max-nodes
• Flags shortcuts added
• Tests added for output handler
• File creation in tests refactored

Version 1.1.9¶

• Use fields in the CSV file such that the CSV file is consistent

Version 1.1.8¶

• Fixed typos

Version 1.1.7¶

• Bugfix: sometimes crashes randomly (solved by introducing intertime)
• Bugfix: added interlogin time to overcome SSH security issues
• Added port as parameter in the INI file

Version 1.1.6¶

• Bugfix: ansering “yes” automatically to the quest “Are you sure you want to continue connecting?”
• Removed retries for connecting

Version 1.1.5¶

• Versioning fix

Version 1.1.4¶

• Fix decoding bug

Version 1.1.3¶

• Change version

Version 1.1.2¶

• Change version

Version 1.1.1¶

• Change version

Version 1.1.0¶

• Final merge

Version 1.0.5¶

• Set default verbose level to verbose
• Install setup methods for automatically installing software on the external server
• Changed documentation style
• Better logging
• Additional plugin settings

Version 1.0.4¶

• Set Travis branch to master

Version 1.0.3¶

• Added standard_output as default output method
• Added the “v” and “vv” flags to the documentation
• Added CTRL+C to get out the ISA application
• Added the “free -m” plugin
• Added the “collectl” plugin

Version 1.0.2¶

• Changed version number
• Fixed ReadTheDocs

Version 1.0.1¶

• Changed version number

Version 1.0.0¶

• Added plugin infrastructure
• Added output handling
• Added monitor class
• Added input handling
• Added SSH server connection

Version 0.2.0¶

• Initial project code

Version 0.1.0¶

• Project scaffolding