GeralexGR

May 4, 2022May 4, 2022

Download latest file from blob storage through az cli

Given that you have a blob storage container with multiple files, you could download the most latest one easily with az cli

In my scenario I have a container named backups which includes multiple MS SQL backups. I wanted to download the latest in order to restore through a pipeline on SQL server.

In order to accomplish that you should first login with az cli.

az login

If this is not possible through automation you would have to create a managed identity for your resource. The code is uploaded on the below gist.

	$container_name_input = "backups"
	$sg_con_string = "XXX"
	$json = az storage blob list –container-name $container_name_input –connection-string $sg_con_string \| ConvertFrom-Json \| Sort-Object -Descending { $_.properties.CreationTime } \| Select-Object name
	az storage blob download –file $json[0].name –name $json[0].name –container-name $container_name_input –connection-string $sg_con_string

view raw download-latest-blob-storage-account-az-cli hosted with ❤ by GitHub

You should replace your connection string by getting yours under access keys.

If you remove descending date the default value would be Ascending.

By executing the script you will get a json output like the below:

May 1, 2022May 2, 2022

Powershell -Contains does not evaluate string with Get-Content

When using powershell contains method you should be aware of the type of the object that is used.

Lets examine the below string which was used with contains on a powershell script.

Processed 384 pages for database ‘restore’, file ‘restore’ on file 1.
Processed 2 pages for database ‘restore’, file ‘restore_log’ on file 1.
RESTORE DATABASE successfully processed 386 pages in 0.004 seconds (752.929 MB/sec).

The string was stored on $result variable and I wanted to capture if a specific string was included in the variable. Although the string is included in the variable the result was false.

After investigating I was able to figure that the object type of the $result variable was an object and Contains could not evaluate successfully

In this situation you would have to cast the object on a string data type to evaluate correctly.

For example when using Get-Content you could cast to a string like below.

[string]$result = Get-Content C:\Users\galexiou\Desktop\2.txt

Then the object type will be of type string

The evaluation will work as expected.

April 29, 2022May 2, 2022

Azure DevOps agent cannot checkout GitHub repository

Recently I faced an issue with my Azure DevOps self hosted container agents. They could not checkout the git repositories and the build stopped due to the default timeout of 60 minutes per run.

This happened for multiple builds, as a result I had to investigate the reason behind this error.

By checking the logs inside the container on the C:\agent\_diag folder I could recognize an error message like the below:

A session for this agent already exists.
Agent connect error: The task agent xxx already has an active session for owner xxx.. Retrying until reconnected.

By searching online, I figured out that this is a reported bug on previous agents versions. In order to resolve, I updated and reconfigured the agent. You can update the agent, either from the GUI or by creating a new container and installing the latest version of azure devops agent.

In order to reconfigure the agent I first took an interactive shell on it.

docker exec -it agent-name powershell.exe

Then inside C:\agent run the below commands.

Reconfigure the agent

This is a temporary fix for your agent. If the problem persists you should open a support ticket on Microsoft to troubleshoot the issue.

April 18, 2022April 28, 2022

Install and configure kubernetes dashboard for Docker Desktop local cluster

Kubernetes dashboard is a helpful UI application that presents all your resources inside your k8s cluster. As most people prefer GUI instead of single commands, this tool can make your k8s administration experience better.

When you install docker desktop on your local or development machines, you can select to also include a k8s installation with it. You can locate all your Kubernetes settings using the Docker Desktop UI.

The local cluster is composed of only one node, the computer itself.

In order to install dashboard first run the below kubectl apply command:

kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.5.0/aio/deploy/recommended.yaml

Then you will need to run kubectl proxy

Then open GUI Dashboard.

Kubernetes Dashboard

The below dialog will appear.

We will examine the Token example.

Create and save the below definition as s.yml. Then apply this configuration with kubectl apply -f s.yml

apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: kubernetes-dashboard

Create and save the below definition as r.yml. Then apply this configuration with kubectl apply -f r.yml

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: admin-user
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: admin-user
  namespace: kubernetes-dashboard

Then run the below command:

kubectl -n kubernetes-dashboard get secret $(kubectl -n kubernetes-dashboard get sa/admin-user -o jsonpath="{.secrets[0].name}") -o go-template="{{.data.token | base64decode}}"

The output will be your Token.

Paste the Token on the previous link, and then you will have a working dashboard for your local cluster.

You can also skip the Token procedure. Simply run the below command:

kubectl patch deployment kubernetes-dashboard -n kubernetes-dashboard --type 'json' -p '[{"op": "add", "path": "/spec/template/spec/containers/0/args/-", "value": "--enable-skip-login"}]'

Then you will see a skip button near the sign in

Kubernetes dashboard:

Deploy and Access the Kubernetes Dashboard | Kubernetes

Token procedure:

dashboard/creating-sample-user.md at master · kubernetes/dashboard (github.com)