Docker run results in “host not found in upstream” error
I have a frontend-only web application hosted in Docker. The backend already exists but it has “custom IP” address, so I had to update my local /etc/hosts file to access it. So, from my local machine I am able to access the backend API without problem.
But the problem is that Docker somehow can not resolve this “custom IP”, even when the host in written in the container (image?) /etc/hosts file.
When the Docker container starts up I see this error
$ docker run media-saturn:dev 2016/05/11 07:26:46 [emerg] 1#1: host not found in upstream "my-server-address.com" in /etc/nginx/sites/ms.dev.my-company.com:36 nginx: [emerg] host not found in upstream "my-server-address.com" in /etc/nginx/sites/ms.dev.my-company.com:36
I update the /etc/hosts file via command in Dockerfile, like this
# install wget RUN apt-get update \ && apt-get install -y wget \ && rm -rf /var/lib/apt/lists/* # The trick is to add the hostname on the same line as you use it, otherwise the hosts file will get reset, since every RUN command starts a new intermediate container # it has to be https otherwise authentification is required RUN echo "22.214.171.124 my-server-address.com" >> /etc/hosts && wget https://my-server-address.com
When I ssh into the machine to check the current content of /etc/hosts, the line “126.96.36.199 my-server-address.com” is indeed there.
Can anyone help me out with this? I am Docker newbee.
One Solution collect form web for “Docker run results in “host not found in upstream” error”
I have solved this. There are two things at play.
One is how it works locally and the other is how it works in Docker Cloud.
- cd into root of project, where Dockerfile is located
- build image:
docker build -t media-saturn:dev .
- run the builded image:
docker run -it --add-host="my-server-address.com:188.8.131.52" -p 80:80 media-saturn:dev
Docker cloud workflow
extra_hostdirective to your Stackfile, like this
and then click Redeploy in Docker cloud, so that changes take effect
- ignore as many folders as possible to speed up process of sending data to docker deamon
- add .dockerignore file
- typically you want to add folders like
- in my case the
tmpcontained about 1.3GB of small files, so ignoring it sped up the process significantly