Powershell to get list of hosts

General
1

How can I use Powershell to get a list of hosts from CheckMK - the same as doing a ‘Host Search’ with hostname as blank?

Also, need to be able to work past first search limited to 1,000 entries and get all entries.

If I can get the webpage that is displayed I can parse it to extract out the hostnames.

2

Hi,
do you mean something like that:
http://CMK/SITE/check_mk/view.py?view_name=allhosts
or
http://CMK/SITE/check_mk/view.py?view_name=allhosts&_username=automation&_secret=YourSecret
or
http://CMK/SITE/check_mk/view.py?view_name=allhosts&_username=automation&_secret=YourSecret&output_format=json

Karl

3

I want to use PowerShell to query CheckMK to get a list of hostname that would display on the webpage when doing a ‘Host Search’ webpage click.

Currently I go to the webpage and select all (Ctrl-A) then copy and paste results in a text file and then parse the file to extract to hostname.

4

Hi,
I don’t know Powershell. But I think it’s possible to retrieve information via URLs. You can use the posted URLs in your script. Instead of json, it’s also possible to get python or csv data.

Karl

5

You can check this link, you will find your solution:

1 Like
6

This is very promising - thanks.
I have two items though.

  1. I had to add -UseBasicParsing in the line below due to a message about Internet Explorer. I’m not sure if this will affect anything, or more specifically #2 below. I have another script where I interrogate webpages where I had to do this with no other issues.

$result = Invoke-WebRequest -Uri $URI -Method Post -Body $postParams -UseBasicParsing

  1. I’m getting a web response of:
    StatusCode : 200
    StatusDescription : OK
    Content : ERROR: Invalid automation secret for user myusername

I 100% know that the password I’m using is correct.
I assume $mycheckmkuser and $mycheckmsecret are to be set with the username and password I use to log into CheckMK.

I don’t know how to get past this issue.

1 Like
7

You should use automation user(special for API)

8

I’m not sure what that is. Where do I look in our NAgios/CheckMK configuration to find it?

9

Users-create new user and choose option with automation secret

10

Thanks immensely that worked. I have the results I was looking for.

1 Like
11

@darusdp If you want, you can Post your solution here for another member :slight_smile:

12

I kept your coding style but added more error checking and a switch for UseBasicParsing. That code could be incorporated into your other functions

Declaration of a function to get host(s) in check_mk based on RegEx of hostname

function GetCheckmkHost
{
# parameter definition
param(
[Parameter(Position=0, Mandatory=$true)]
[string]$checkmkserver,
[Parameter(Position=1, Mandatory=$true)]
[string]$checkmkinstance,
[Parameter(Position=2, Mandatory=$true)]
[string]$checkmkuser,
[Parameter(Position=3, Mandatory=$true)]
[string]$checkmksecret,
[Parameter(Position=4, mandatory=$true)]
[string]$hostname,
[Parameter(mandatory=$false)]
[bool]$https = $false,
[Parameter(mandatory=$false)]
[switch]$usebasicparsing = $false
)

#######################
# variable definition #
#######################

# declare return variable for the function as hashtable
$return = @{}

# decide wether to use https or not
if ($https)
{
    $URI = "https://"
}
else
{
    $URI = "http://"
}

$URI += "$checkmkserver/$checkmkinstance/check_mk/view.py"

# build the web request for displaying the host with its status
$postParams = @{
_username=$checkmkuser
_secret=$checkmksecret
_transid='-1'
host_regex=$hostname # the hostname to search for
view_name='allhosts'
output_format='json'
}

# execute the web request
try
{
 if ($usebasicparsing)
 {
  $result = Invoke-WebRequest -Uri $URI -Method Post -Body $postParams -UseBasicParsing #DPD 11-24-2020 added -UseBasicParsing
 }
 else
 {
  $result = Invoke-WebRequest -Uri $URI -Method Post -Body $postParams
 }
}
catch
{
 $return.status = 1
 $return.msg = "error while connecting the check_mk api.`r`n$($error[0])"
 # return the error
 Return $return
}

# check if a respones was getting back
if (!$result)
{
    Write-Host "error while connecting the check_mk api."
    Write-Host
    $return.status = 1
    $return.msg = "error while connecting the check_mk api."
    # return the error
    Return $return
}

# check if the web request was successful
if ($result.StatusCode -ne 200 -or $result.Content.StartsWith('ERROR:'))
{
    Write-Host "error in the response from the check_mk api."
    Write-Host
    Write-Host $result
    $return.status = 1
    $return.msg = "error in the response from the check_mk api."
    # return the error
    Return $return
}

# convert the string content of the response into a powershell json object
$json = $result.content | convertfrom-json

# build array of property names
$field = @('')*($json[0].Count)
for ($i=0; $i -lt $json[0].Count; $i++ )
{
 $field[$i] = $json[0][$i]
}

# loop thru all hosts in results to build array of host objects
$hosts = @()
for ($j = 1; $j -lt $json.Count; $j++)
{
 $obj = New-Object PSObject
 for ($i=0; $i -lt $field.Count; $i++)
 {
  Add-Member -InputObject $obj -MemberType NoteProperty -Name $field[$i] -Value $json[$j][$i]
 }
 $hosts += @($obj)
}
$return.status = 0
$return.msg = "found no errors with host $hostname"
$return.host = $hosts
# return the error or the success message
Return $return

}

###########End of function declarations#######################

############

Example

############

connection variables

$mycheckmkserver = “insert checkmk servername”
$mycheckmkinstance = “insert checkmk instance”
$mycheckmkuser = “insert checkmk username using automation secret”
$mycheckmksecret = “insert checkmk automation secret of the username”

host to be checked, set downtime, patched, removed downtime and checked again

$myhost = '.’ # . means all or

execute function to get Checkmk host(s)

$result = GetCheckmkHost -checkmkserver $mycheckmkserver -checkmkinstance $mycheckmkinstance -checkmkuser $mycheckmkuser -checkmksecret $mycheckmksecret -hostname $myhost -usebasicparsing

if host was not healthy, write error and exit

if ($result.status -ne 0)
{
Write-Host “check_mk says the host $myhost is not healthy. Stopping script.”
Write-Output $result.msg
exit
}

#output hostnames to file
foreach ($hostobj in $result.host)
{
Write-Output $hostobj.host
}
exit

1 Like
13

Thank you @darusdp :slight_smile:

14

New issue, in checkmkdowntime at:
$URI += “$checkmkserver/$checkmkinstance/check_mk/webapi.py”
#build the web request for checking if the host exists in check_mk
$Body = @{
action=“get_host”
_username=$checkmkuser
_secret=$checkmksecret
request_format=“json”
output_format=“json”
hostname=$hostname
}

$result = Invoke-WebRequest -Uri $URI -Method Post -Body $Body -UseBasicParsing
.
.
.
if ( ($result.content | ConvertFrom-Json).result_code -ne 0 )

$result.content = {“result”: “Hostname is missing”, “result_code”: 1}

Yet, in $Body hostname is set correct. The same hostname that work with function checkmkhealth

Any ideas?

15

you need something like this:

?_do_confirm=Yes&_do_actions=yes&_transid=-1&view_name=hoststatus&site=&_ack_sticky=on&_ack_otify=off&output_format=JSON&_username=&_secret=&_down_comment=$YOURComment&_down_from_now=From+now+for&_down_minutes=$DurationInMin&host=$hostname

16

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