On my Docker quest I was surprised once again. I wanted to share my drive with my Docker container. I was presented with a login dialog that asked for my Azure AD credentials. Azure AD credentials? Seriously? Do I have Azure AD credentials?

UPDATE 9 November 2018

It turns out you do not have to use an Azure AD account for Shared Drives at all. You can just create a local account (i.e. DockerHost) using the instructions below points 2 to 4 .

The confusing part is that the dialog displayed the username as AzureAD\MyName. This didn’t ring a bell. After fiddling around I figured out that I could use my Office 365 credentials, but the username needed to be changed to my email address in the following format AzureAD\[email protected]. Go figure.

After logging in nothing happened and the share was unchecked again. WTF?!?!

After googling around I found the following post Sharing your C drive with Docker for Windows when using Azure Active Directory by Tom Chantler, which gave me enough information to fix the problem.

I had to make to three changes to the solution he describes in his post:

1. I do not have Azure AD credentials. So I used my Office 365 credentials, which also uses Azure AD. So instead of the username being AzureAD\MyName, I had to change it to AzureAD\[email protected].
2. I’m running Windows 10 Professional. It initially would not let me create a local users who’s username was not an email address. In the first dialog I needed to select ‘I don’t have this person’s sign-in information’ and in the next step ‘Add user without Microsoft account’. Then I could create the user with the same username (MyName) without the Azure\ prefix.
3. Change the account type to Administrator.
4. Go to the Docker Settings and select Shared Drives and use the local user account created in the previous step to authenticate. It should work now.

After that the C drive was shared. Whooha!

I’m reacquainting myself with Docker. My first steps were dodgy. I immediately ran into problems testing if Docker was installed correctly on my Windows 10 machine, when I wanted to execute the hello-world image.

docker run hello-world

Which threw the following error.

Unable to find image 'hello-world:latest' locally
docker: Error response from daemon: Get https://registry-1.docker.io/v2/library/hello-world/manifests/latest: unauthorized: incorrect username or password.
See 'docker run --help'.

It turned out the problem was that I was a little to eager when I signed into the Docker Hub in the Docker Settings.

After logging out with the following command it worked.

docker logout

Go figure…