Unable to get communication between two rootfull containers with podman

Question

I have two nginx containers running.

One is listening on port 80 the other 8080.

Here is how I run them:

sudo podman run --rm \
 -t \
 -p 8080:80 \
 --publish-all \
 --name nginx-two \
 -v ./html2/:/usr/share/nginx/html \
 -v ./html2/conf/default.conf:/etc/nginx/conf.d/default.conf \
 -d nginx

The second:

sudo podman run --rm -t -p 80:80 --name nginx -v ./html/:/usr/share/nginx/html -v ./html/conf/conf.d:/etc/nginx/conf.d -d nginx

NGiNX config:

location / {
    proxy_pass http://10.88.0.37:8080;
}

I also tried:

location / {
    proxy_pass http://127.0.0.1:8080;
}

This config is used by the --name=nginx container.

Here is the error I get:

2020/01/26 15:33:05 [error] 8#8: *1 connect() failed (111: Connection refused) while connecting to upstream, client: 10.88.0.1, server: , request: "GET / HTTP/1.1", upstream: "http://127.0.0.1:8080/", host: "localhost"
10.88.0.1 - - [26/Jan/2020:15:33:05 +0000] "GET / HTTP/1.1" 502 157 "-" "Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Firefox/68.0" "-"

Is there way to make these containers communicate with each other?

I also tried using --pod. But then got this error:

Error: cannot set port bindings on an existing container network namespace

Answer 1

You should not use --publish-all, as the man page of podman-run indicates this publishes all exposed ports to random ports of the host interface. The -p option is therefore sufficient.

Creating a dedicated network where both containers would be could help with your issue, you could then reference it by using the --network=network-id option of the run command.

When using pods, the port mappings should be defined on the pod itself, not on the containers within that pod:

podman pod create --name mypod -p 80:80

It would not be possible to run in a single pod with two nginx instances due to conflicting ports 80. (it uses the exposed ports of the image)

Red Hat published a good explanation: https://www.redhat.com/sysadmin/container-networking-podman