system test image: build it multiarch

buildah now supports running under emulation[1] as well as
creating manifests. Use those features to create a multiarch
testimage that can be used to test podman on other arches.

 [1] on Fedora 33, this requires the qemu-user-static package

We also build a new :00000001 image, replacing :00000000,
because (sigh) some tests try to run 'true' in the container.
Include instructions on building said image.

Signed-off-by: Ed Santiago <santiago@redhat.com>

test/system/030-run.bats

@@ -139,7 +139,7 @@ echo $rand        |   0 | $rand
     is "$output" "" "--pull=never [present]: no output"
 
     # Now test with a remote image which we don't have present (the 00 tag)
-    NONLOCAL_IMAGE="$PODMAN_TEST_IMAGE_REGISTRY/$PODMAN_TEST_IMAGE_USER/$PODMAN_TEST_IMAGE_NAME:00000000"
+    NONLOCAL_IMAGE="$PODMAN_NONLOCAL_IMAGE_FQN"
 
     run_podman 125 run --pull=never $NONLOCAL_IMAGE true
     is "$output" "Error: unable to find a name and tag match for $NONLOCAL_IMAGE in repotags: no such image" "--pull=never [with image not present]: error"
@@ -175,7 +175,7 @@ echo $rand        |   0 | $rand
 # 'run --rmi' deletes the image in the end unless it's used by another container
 @test "podman run --rmi" {
     # Name of a nonlocal image. It should be pulled in by the first 'run'
-    NONLOCAL_IMAGE="$PODMAN_TEST_IMAGE_REGISTRY/$PODMAN_TEST_IMAGE_USER/$PODMAN_TEST_IMAGE_NAME:00000000"
+    NONLOCAL_IMAGE="$PODMAN_NONLOCAL_IMAGE_FQN"
     run_podman 1 image exists $NONLOCAL_IMAGE
 
     # Run a container, without --rm; this should block subsequent --rmi

test/system/070-build.bats

@@ -305,8 +305,10 @@ Cmd[0]             | /bin/mydefaultcmd
 Cmd[1]             | $s_echo
 WorkingDir         | $workdir
 Labels.$label_name | $label_value
-Labels.\"io.buildah.version\" | $buildah_version
 "
+    # FIXME: 2021-02-24: Fixed in buildah #3036; reenable this once podman
+    #        vendors in a newer buildah!
+    # Labels.\"io.buildah.version\" | $buildah_version
 
     parse_table "$tests" | while read field expect; do
         actual=$(jq -r ".[0].Config.$field" <<<"$output")

test/system/build-testimage

@@ -12,6 +12,9 @@
 # still need a fedora image for that.
 #
 
+# Buildah binary
+BUILDAH=${BUILDAH:-buildah}
+
 # Tag for this new image
 YMD=$(date +%Y%m%d)
 
@@ -58,7 +61,8 @@ chmod 755 pause
 #    - check for updates @ https://hub.docker.com/_/alpine
 # busybox-extras provides httpd needed in 500-networking.bats
 cat >Containerfile <<EOF
-FROM docker.io/library/alpine:3.12.0
+ARG ARCH=please-override-arch
+FROM docker.io/\${ARCH}/alpine:3.12.0
 RUN apk add busybox-extras
 ADD testimage-id pause /home/podman/
 LABEL created_by=$create_script
@@ -69,26 +73,44 @@ EOF
 
 # --squash-all    : needed by 'tree' test in 070-build.bats
 podman rmi -f testimage &> /dev/null || true
-podman build --squash-all -t testimage .
+
+# We need to use buildah because (as of 2021-02-23) only buildah has --manifest
+# and because Dan says arch emulation is not currently working on podman
+# (no further details).
+# Arch emulation on Fedora requires the qemu-user-static package.
+for arch in amd64 ppc64le s390x;do
+    ${BUILDAH} bud \
+               --arch=$arch \
+               --build-arg ARCH=$arch \
+               --manifest=testimage \
+               --squash \
+               .
+done
 
 # Clean up
 cd /tmp
 rm -rf $tmpdir
 
-# Tag and push to quay.
+# Tag image and push (all arches) to quay.
-podman tag testimage quay.io/libpod/testimage:$YMD
+remote_tag=quay.io/libpod/testimage:$YMD
-podman push quay.io/libpod/testimage:$YMD
+podman tag testimage ${remote_tag}
+${BUILDAH} manifest push --all  ${remote_tag} docker://${remote_tag}
 
-# Side note: there should always be a testimage tagged ':00000000'
+# Side note: there should always be a testimage tagged ':0000000<X>'
-# (eight zeroes) in the same location; this is used by tests which
+# (eight digits, zero-padded sequence ID) in the same location; this is
-# need to pull a non-locally-cached image. This image will rarely
+# used by tests which need to pull a non-locally-cached image. This
-# if ever need to change, nor in fact does it even have to be a
+# image will rarely if ever need to change, nor in fact does it even
-# copy of this testimage since all we use it for is 'true'.
+# have to be a copy of this testimage since all we use it for is 'true'.
+# However, it does need to be multiarch :-(
 #
-# As of 2020-09-02 it is simply busybox, because it is super small:
+# As of 2021-02-24 it is simply busybox, because it is super small,
+# but it's complicated because of multiarch:
 #
-#    podman pull docker.io/library/busybox:1.32.0
+#    img=quay.io/libpod/testimage:00000001
-#    podman tag  docker.io/library/busybox:1.32.0 \
+#    buildah manifest create $img
-#                quay.io/libpod/testimage:00000000
+#    for arch in amd64 ppc64le s390x;do
-#    podman push quay.io/libpod/testimage:00000000
+#        buildah pull --arch $arch docker.io/$arch/busybox:1.32.0
+#        buildah manifest add $img docker.io/$arch/busybox:1.32.0
+#    done
+#    buildah manifest push --all $img docker://$img
 #

test/system/helpers.bash

@@ -7,9 +7,14 @@ PODMAN=${PODMAN:-podman}
 PODMAN_TEST_IMAGE_REGISTRY=${PODMAN_TEST_IMAGE_REGISTRY:-"quay.io"}
 PODMAN_TEST_IMAGE_USER=${PODMAN_TEST_IMAGE_USER:-"libpod"}
 PODMAN_TEST_IMAGE_NAME=${PODMAN_TEST_IMAGE_NAME:-"testimage"}
-PODMAN_TEST_IMAGE_TAG=${PODMAN_TEST_IMAGE_TAG:-"20200929"}
+PODMAN_TEST_IMAGE_TAG=${PODMAN_TEST_IMAGE_TAG:-"20210223"}
 PODMAN_TEST_IMAGE_FQN="$PODMAN_TEST_IMAGE_REGISTRY/$PODMAN_TEST_IMAGE_USER/$PODMAN_TEST_IMAGE_NAME:$PODMAN_TEST_IMAGE_TAG"
 
+# Remote image that we *DO NOT* fetch or keep by default; used for testing pull
+# This changed from 0 to 1 on 2021-02-24 due to multiarch considerations; it
+# should change only very rarely.
+PODMAN_NONLOCAL_IMAGE_FQN="$PODMAN_TEST_IMAGE_REGISTRY/$PODMAN_TEST_IMAGE_USER/$PODMAN_TEST_IMAGE_NAME:00000001"
+
 # Because who wants to spell that out each time?
 IMAGE=$PODMAN_TEST_IMAGE_FQN