Saturday, April 13, 2019

Ubuntu 18.04 + Docker Setup

I am setting up a new Docker Engine running on Ubuntu 18.04
During the Ubuntu installation, I selected Docker Engine as part of the deployment setup. By default the Docker Engine Service is run by Snap.

My environment uses web proxy to hit the Internet and internal DNS servers only are allowed. Docker Daemon or Docker Containers must use web proxy and internal DNS to hit the Internet.

To setup Ubuntu with static IP, pointing to the right DNS, netplan must be created
create a YAML file in the /etc/netplan/

> sudo vi /etc/netplan/99-local-init.yaml

version: 2
renderer: networkd
search: [domainlocal.tld]
addresses: [, 10.0.03]

ps: addresses: [,] are the local DNS servers

To get Docker Engine to use web proxy and local DNS servers, Drop-In configuration files must be created. Check the Docker Engine service name under /etc/systemd/system/ folder. My Ubuntu 18.04 installation has got snap.docker.dockerd.service name

Create a folder with the same name of the service name and add ".d" at the end of the folder name

> sudo mkdir -p /etc/systemd/system/snap.docker.dockerd.service.d 

Then you can create as many as .conf files in that folder

To create web proxy configuration

> sudo vi /etc/systemd/system/snap.docker.dockerd.service.d/proxy.conf

Environment="HTTP_PROXY=http://myproxy.domainlocal.tld:8080/" "HTTPS_PROXY=http://myproxy.domainlocal.tld:8080/" "NO_PROXY=localhost,*.domainlocal.tld"

To create DNS setting

> sudo vi /etc/systemd/system/snap.docker.dockerd.service.d/dns.conf

ExecStart=/usr/bin/snap run docker.dockerd --dns --dns --dns-search domainlocal.tld

ps: ExecStart= must be defined in the first line to reset that flag

The daemon must be restarted

> sudo systemtcl daemon-reload
> sudo systemctl restart snap.docker.dockerd

To build / run process within the Docker Container, pass the flags:

> sudo docker build --build-arg http_proxy=http://myproxy.domainlocal.tld:8080 --build-arg https_proxy=http://myproxy.domainlocal.tld:8080 -t dockerhubname/imangename .

Have fun!

Tuesday, March 12, 2019

Docker Copy Files

When building a Docker image using the Dockerfile, if you need to copy some files from the Docker Engine machine to the Docker Image, you need to use the "correct" source path where the files are located.

Let's say you have the following files:


you can't specify the following command within your Dockerfile

COPY /mydocker/ /etc/
COPY /mydocker/ /etc/

instead, you need to do the following

mkdir /mydocker/resources
mv /mydocker/ /mydocker/resources
mv /mydocker/ /mydocker/resources

then, in your Dockerfile, specify the following COPY command

COPY resources /etc/

Tuesday, January 01, 2019

Windows Server Core 2019 - Remote PowerShell

Just installed a couple of Windows Server Core 2019. To manage them through PowerShell remotely, you need to enable PowerShell Remoting

On the Windows Server 2019 Core, run the following command

> Enable-PSRemoting -Force

The remote machine from which you want to manage the server

> Enter-PSSession -Credential (Get-Credential) -ComputerName my2019server.domain.tld