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What will be the best way to handle these scenarios, if they are not one-time, but regular:

  • Self-hosted services on a quite a bunch of machines are needed to be repointed to different database in a centralized way. So it requires changing app.configs and restarting services.
  • All services need to get new logging configuration ( for example ), say update section in App.config and restart

Of course this can be automated using powershell, but there definitely are tools for that. I know, that some companies use Configuration Management Systems for that - like Salt, Ansible, Chef or Puppet, but are they suited for this kind of task.

I also now about Java solution Spring cloud config, but haven't found something like this for .NET

Andrey Ershov
  • 133

1 Answers1

1

The tasks you are describing can be solved in multiple ways. No one way is "best" as each has its own pros and cons.

The industry as a whole has been evolving from scripts, to configuration management to immutable systems.

As an example, to manage the web.config of an IIS web server, you issue appcmd.exe commands. We use Chef and the IIS cookbook to abstract the appcmd.exe command idempotent resources. 

  iis_config "session sql_provider" do
    cfg_cmd "Foobar/#{site} -section:system.web/sessionState /+\"providers.[name='#{session_name}',connectionString='#{session_connection_string}',type='#{session_type}']\""
    action :set
      notifies :restart, 'iis_site[mysite]'
  end

Here everything inside '#{}' is a chef variable. If the resource runs, it triggers a restart of the IIS service.

The advantage of not using appcmd.exe directly, but abstracting it away to a resource, is that a resource can easily take variables as parameters. This way you can write your code once, but use it in multiple datacenters and environments. The end goal is to be able to write a policy for every type of server, and let the configuration management put the server in alignment with the policy.

Another example of managing a logging config file inside chef. 

template "#{node['web']['path']}/log4net.config.xml" do
  source 'wwwroot/log4net.config.erb'
  variables(
    :log_level => node['web']['log4net']['log_level']
  )
  action :create
end

The xml file is then "templateized" as an erb template. Everything inbetween <%= -%> is a variable

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <log4net>
    <root>
      <level value="<%= @log_level -%>"/>

You can then run chef on a schedule, so that if the variable ever changes. The config management puts the file into the desired state.

Ansible,Chef,Puppet and Salt all operate on very similar principles.

spuder
  • 10,135