Dear Maintainer,

I am seeing DNS resolution fail when using 'podman build' but succeed when
using 'podman run', with a Dockerfile which contains the same commands I run
manually in the 'podman run'-launched shell.

Dockerfile
----------
FROM alpine:3.10
RUN cat /etc/resolv.conf
RUN apk add tar

'podman run'
----------
kpfleming@nvr21:~/ctr-dns$ podman run --rm -it alpine:3.10 /bin/sh
/ # cat /etc/resolv.conf
nameserver 10.0.2.3
nameserver 2001:470:8afe:255::2
options edns0 trust-ad
/ # apk add tar
fetch http://dl-cdn.alpinelinux.org/alpine/v3.10/main/x86_64/APKINDEX.tar.gz
fetch http://dl-
cdn.alpinelinux.org/alpine/v3.10/community/x86_64/APKINDEX.tar.gz
(1/1) Installing tar (1.32-r1)
Executing busybox-1.30.1-r5.trigger
OK: 6 MiB in 15 packages
/ # exit

`podman build`
----------
kpfleming@nvr21:~/ctr-dns$ podman build .
STEP 1/3: FROM alpine:3.10
STEP 2/3: RUN cat /etc/resolv.conf
--> Using cache
6e684b0a8063a3c6ea051cc28b16ea19cc984ba9f154810cc3235d10e2ad4b2b
--> 6e684b0a806
STEP 3/3: RUN apk add tar
fetch http://dl-cdn.alpinelinux.org/alpine/v3.10/main/x86_64/APKINDEX.tar.gz
ERROR: http://dl-cdn.alpinelinux.org/alpine/v3.10/main: temporary error (try
again later)
WARNING: Ignoring http://dl-cdn.alpinelinux.org/alpine/v3.10/main: No such file
or directory
fetch http://dl-
cdn.alpinelinux.org/alpine/v3.10/community/x86_64/APKINDEX.tar.gz
ERROR: http://dl-cdn.alpinelinux.org/alpine/v3.10/community: temporary error
(try again later)
WARNING: Ignoring http://dl-cdn.alpinelinux.org/alpine/v3.10/community: No such
file or directory
ERROR: unable to select packages:
  tar (no such package):
    required by: world[tar]
Error: building at STEP "RUN apk add tar": while running runtime: exit status 1

When I add 'strace' to the image and trace the 'apk' invocation, I see that the
DNS queries sent to the servers listed in /etc/resolv.conf both time out, when
using 'podman build'.

I have tested the 4.4 package from 'experimental' with no change in behavior.

Hi Kevin,

great to hear from you in this space!
Also, maybe upstream has an idea, can you please report this issue at
https://github.com/containers/podman/issues/new/choose. In any case, here
is the output that I get:

siretart@x1:/tmp/dnstest$ cat >> Containerfile
FROM alpine:3.10
RUN cat /etc/resolv.conf
RUN apk add tar
siretart@x1:/tmp/dnstest$ cat Containerfile
FROM alpine:3.10
RUN cat /etc/resolv.conf
RUN apk add tar
siretart@x1:/tmp/dnstest$ podman build .
STEP 1/3: FROM alpine:3.10
Resolved "alpine" as an alias
(/etc/containers/registries.conf.d/shortnames.conf)
Trying to pull docker.io/library/alpine:3.10...
Getting image source signatures
Copying blob 396c31837116 done
Copying config e7b300aee9 done
Writing manifest to image destination
Storing signatures
STEP 2/3: RUN cat /etc/resolv.conf
search int.tauware.de
nameserver 10.0.2.3
nameserver 192.168.88.3
--> 2ce59772eaf
STEP 3/3: RUN apk add tar
fetch http://dl-cdn.alpinelinux.org/alpine/v3.10/main/x86_64/APKINDEX.tar.gz
fetch
http://dl-cdn.alpinelinux.org/alpine/v3.10/community/x86_64/APKINDEX.tar.gz
(1/1) Installing tar (1.32-r1)
Executing busybox-1.30.1-r5.trigger
OK: 6 MiB in 15 packages
COMMIT
--> 7c1bfd9e030
7c1bfd9e030f07b05cc9427a97c0bc5ff73bca5436bce389ad81da1a64f64a11

Confirmed; I can no longer reproduce the problem. Something somewhere in the stack got fixed :-)

Glad to hear it!

Thanks for confirming!