After you have installed Checkmk on a Linux server, you will learn here what still needs to be done to create, start and fill a site with life by adding the first devices to the monitoring - and to complete everything in just a few steps.
Note: If you are running Checkmk with one of our appliances or in a Docker container instead of on a Linux server, the site management runs differently than described below:
Checkmk appliances are administered via a special web interface that also covers the creation of sites, which is explained in the article about the appliance.
With the installation as Docker container, the site cmk is set up and started at the same time.
In both cases, you can therefore jump straight to the login to the web interface.
1. Creating a site
Create the first site as root with the omd create command followed by the name of the site.
The name may only consist of letters and numbers.
The convention here is lower case letters.
In the User guide, we use the name mysite in all examples.
root@linux$ omd create mysite
Adding /opt/omd/sites/mysite/tmp to /etc/fstab.
Creating temporary filesystem /omd/sites/mysite/tmp...OK
Updating core configuration...
Generating configuration for core (type cmc)...Creating helper config...OK
OK
Restarting Apache...OK
Created new site mysite with version 2.0.0.cee.
The site can be started with omd start mysite.
The default web UI is available at http://linux/mysite/
The admin user for the web applications is cmkadmin with password: jEpCM9T4
For command line administration of the site, log in with 'omd su mysite'.
After logging in, you can change the password for cmkadmin with 'htpasswd etc/htpasswd cmkadmin'.As you can see in the command output, when the site is created, an administrative Checkmk user with the name cmkadmin is automatically created, which you can use to log in to the Checkmk web interface.
cmkadmin has been given a random password.
Make a note of this password — or change it.
You will learn how to do this in the next paragraph but one.
Once you have created the new site, subsequent administration is no longer carried out as the root, but instead as the site user.
The easiest way to become a site user is with the following command:
root@linux$ su - mysite
OMD[mysite]:~$As a site user, you can change the password of the cmkadmin user as follows:
OMD[mysite]:~$ htpasswd -m etc/htpasswd cmkadmin
New password: *****
Re-type new password: *****
Updating password for user cmkadmin2. Starting a site
A site can be started or stopped. Newly-created sites begin their lives in a stopped state. Therefore, you must start the site by command:
OMD[mysite]:~$ omd start
Creating temporary filesystem /omd/sites/mysite200raw/tmp...OK
Starting mkeventd...OK
Starting rrdcached...OK
Starting npcd...OK
Starting nagios...OK
Starting apache...OK
Starting redis...OK
Initializing Crontab...OKTip: By the way, creating and starting a site is covered in more detail in the Beginner’s guide.
3. Logging on to the web interface
If your Checkmk server is called myserver and your site is called mysite, the web interface is accessed with http://myserver/mysite/ in the browser:
Now log in with the user name cmkadmin and the random password or with the one you changed at the beginning.
This will take you to the start page of Checkmk.
Note: In the Docker container, you can find the password of the user cmkadmin in the log files of the container.
When using the appliance, you set the user name and password yourself when creating the site.
4. Installing an agent on the monitoring server
The very first host you include in the monitoring is the monitoring server itself. To do this, you first need a monitoring agent.
Note: On the appliances this Checkmk agent is already pre-installed.
When working with your own Linux server or in a Docker container you must install the agent yourself. You start in the navigation bar with the Setup menu.
In the 
Checkmk Enterprise Editions, Setup > Agents > Windows, Linux, Solaris, AIX takes you to the download page, which offers you a generic agent that you can download immediately:
In the 
Checkmk Raw Edition, Setup > Agents > Linux will take you to a similarly download page.
Download the package file:
Choose the RPM file format for Red Hat, CentOS and SLES or the DEB file format for Debian and Ubuntu.
Then install the package on your Checkmk server — with rpm -U for the RPM file or with dpkg -i for the DEB file.
For detailed instructions on installing the agent, see Beginner’s guide.
5. Adding the server to the monitoring
The management of the hosts to be monitored can again be found in the Setup menu, more precisely under Setup > Hosts > Hosts.
Click on Add host, enter as Hostname
localhost and click Save & go to service configuration:
In this list, add all the services found but not yet monitored ('undecided') to the monitoring by clicking on Fix all.
Then click on the orange button 3 changes at the top right of the main page to activate the changes on the following page with Activate on selected sites. This takes the new host and its services from the configuration environment into the monitoring environment.
That’s it!
The server will now be monitored with with default settings, which you can see if you display all hosts in the Monitor menu with Monitor > Overview > All hosts and then select the new localhost:
6. Adding more servers and network devices
You can include additional devices to your monitoring in the same way. Here are a couple of hints:
To monitor Windows, use the agent in the MSI package. The Windows agent installs the 'Check MK Service' under Windows.
To monitor SNMP devices such as routers, switches, printers or hardware sensors, use the interface for monitoring already built in by the manufacturer: the SNMP agent. For this, when setting up the host for an SNMP device, select No agent as Checkmk agent. Instead, select as SNMP the SNMP v2 or v3 value. If the SNMP community is not
public, then enter it under SNMP credentials.If the host name cannot be resolved via DNS, activate the IPv4 address parameter in the host properties and enter the IP address by hand.
Tip: If you ever get stuck, we hope you will find the answer to your question in this User guide. If you have questions about details of the Checkmk interface, you can also display the context-sensitive online help: on the main page in the Help menu with Help > Show inline help.