auto-update: simple rollback

Add support for simple rollbacks during `podman auto-update`.  Rollbacks
are enabled by default.  If a systemd unit cannot be restarted after an
update, the previous image will be retagged and the unit will be
restarted a second time.

Add system tests for rollbacks.  Also fix a bug in the restart sequence;
we have to use the channel to actually know whether the restart was
successful or not.

NOTE: To make rollbacks really useful, users must run their containers
with `--sdnotify=container` such that the containers send the ready
message over the (mounted) socket.  This way, restarting the systemd
units during auto update will block until the message has been received
(or a timeout kicked in).

Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

1 files changed, 112 insertions, 5 deletions

diff --git a/test/system/255-auto-update.bats b/test/system/255-auto-update.bats
index 6fb40f41e..4e242e1f1 100644
--- a/test/system/255-auto-update.bats
+++ b/test/system/255-auto-update.bats
@@ -26,9 +26,17 @@ function teardown() {
     done < $SNAME_FILE
 
     rm -f $SNAME_FILE
-    run_podman ? rmi quay.io/libpod/alpine:latest
-    run_podman ? rmi quay.io/libpod/busybox:latest
-    run_podman ? rmi quay.io/libpod/localtest:latest
+    run_podman ? rmi -f                            \
+            quay.io/libpod/alpine:latest           \
+            quay.io/libpod/busybox:latest          \
+            quay.io/libpod/localtest:latest        \
+            quay.io/libpod/autoupdatebroken:latest \
+            quay.io/libpod/test:latest             \
+            quay.io/libpod/fedora:31
+
+    # The rollback tests may leave some dangling images behind, so let's prune
+    # them to leave a clean state.
+    run_podman ? image prune -f
     basic_teardown
 }
 
@@ -43,18 +51,30 @@ function teardown() {
 function generate_service() {
     local target_img_basename=$1
     local autoupdate=$2
+    local command=$3
+    local extraArgs=$4
+    local noTag=$5
+
+    # Unless specified, set a default command.
+    if [[ -z "$command" ]]; then
+        command="top -d 120"
+    fi
 
     # Container name. Include the autoupdate type, to make debugging easier.
     # IMPORTANT: variable 'cname' is passed (out of scope) up to caller!
     cname=c_${autoupdate//\'/}_$(random_string)
     target_img="quay.io/libpod/$target_img_basename:latest"
-    run_podman tag $IMAGE $target_img
+
+    if [[ -z "$noTag" ]]; then
+        run_podman tag $IMAGE $target_img
+    fi
+
     if [[ -n "$autoupdate" ]]; then
         label="--label io.containers.autoupdate=$autoupdate"
     else
         label=""
     fi
-    run_podman run -d --name $cname $label $target_img top -d 120
+    run_podman create $extraArgs --name $cname $label $target_img $command
 
     (cd $UNIT_DIR; run_podman generate systemd --new --files --name $cname)
     echo "container-$cname" >> $SNAME_FILE
@@ -128,6 +148,38 @@ function _confirm_update() {
     _confirm_update $cname $ori_image
 }
 
+@test "podman auto-update - label io.containers.autoupdate=image with rollback" {
+    # Note: the autoupdatebroken image is empty on purpose so it cannot be
+    # executed and force a rollback.  The rollback test for the local policy
+    # is exercising the case where the container doesn't send a ready message.
+    image=quay.io/libpod/autoupdatebroken
+
+    run_podman tag $IMAGE $image
+    generate_service autoupdatebroken image
+
+    _wait_service_ready container-$cname.service
+    run_podman auto-update --dry-run --format "{{.Unit}},{{.Image}},{{.Updated}},{{.Policy}}"
+    is "$output" ".*container-$cname.service,$image:latest,pending,registry.*" "Image update is pending."
+
+    run_podman container inspect --format "{{.Image}}" $cname
+    oldID="$output"
+
+    run_podman inspect --format "{{.ID}}" $cname
+    containerID="$output"
+
+    run_podman auto-update --format "{{.Unit}},{{.Image}},{{.Updated}},{{.Policy}}"
+    is "$output" "Trying to pull.*" "Image is updated."
+    is "$output" ".*container-$cname.service,$image:latest,rolled back,registry.*" "Image has been rolled back."
+
+    run_podman container inspect --format "{{.Image}}" $cname
+    is "$output" "$oldID" "container rolled back to previous image"
+
+    run_podman container inspect --format "{{.ID}}" $cname
+    if [[ $output == $containerID ]]; then
+        die "container has not been restarted during rollback (previous id: $containerID, current id: $output)"
+    fi
+}
+
 @test "podman auto-update - label io.containers.autoupdate=disabled" {
     generate_service alpine disabled
 
@@ -168,6 +220,61 @@ function _confirm_update() {
     _confirm_update $cname $ori_image
 }
 
+@test "podman auto-update - label io.containers.autoupdate=local with rollback" {
+    # sdnotify fails with runc 1.0.0-3-dev2 on Ubuntu. Let's just
+    # assume that we work only with crun, nothing else.
+    # [copied from 260-sdnotify.bats]
+    runtime=$(podman_runtime)
+    if [[ "$runtime" != "crun" ]]; then
+        skip "this test only works with crun, not $runtime"
+    fi
+
+    dockerfile1=$PODMAN_TMPDIR/Dockerfile.1
+    cat >$dockerfile1 <<EOF
+FROM quay.io/libpod/fedora:31
+RUN echo -e "#!/bin/sh\n\
+printenv NOTIFY_SOCKET; echo READY; systemd-notify --ready;\n\
+trap 'echo Received SIGTERM, finishing; exit' SIGTERM; echo WAITING; while :; do sleep 0.1; done" \
+>> /runme
+RUN chmod +x /runme
+EOF
+
+    dockerfile2=$PODMAN_TMPDIR/Dockerfile.2
+    cat >$dockerfile2 <<EOF
+FROM quay.io/libpod/fedora:31
+RUN echo -e "#!/bin/sh\n\
+exit 1" >> /runme
+RUN chmod +x /runme
+EOF
+    image=test
+
+    # Generate a healthy image that will run correctly.
+    run_podman build -t quay.io/libpod/$image -f $dockerfile1
+    podman image inspect --format "{{.ID}}" $image
+    oldID="$output"
+
+    generate_service $image local /runme --sdnotify=container noTag
+    _wait_service_ready container-$cname.service
+
+    run_podman auto-update --dry-run --format "{{.Unit}},{{.Image}},{{.Updated}},{{.Policy}}"
+    is "$output" ".*container-$cname.service,quay.io/libpod/$image:latest,false,local.*" "No update available"
+
+    # Generate an unhealthy image that will fail.
+    run_podman build -t quay.io/libpod/$image -f $dockerfile2
+    podman image inspect --format "{{.ID}}" $image
+    newID="$output"
+
+    run_podman auto-update --dry-run --format "{{.Unit}},{{.Image}},{{.Updated}},{{.Policy}}"
+    is "$output" ".*container-$cname.service,quay.io/libpod/$image:latest,pending,local.*" "Image updated is pending"
+
+    # Note: we rollback automatically by default.
+    run_podman auto-update --format "{{.Unit}},{{.Image}},{{.Updated}},{{.Policy}}"
+    is "$output" ".*container-$cname.service,quay.io/libpod/$image:latest,rolled back,local.*" "Rolled back to old image"
+
+    # Make sure that new container is not using the new image ID anymore.
+    _confirm_update $cname $newID
+}
+
 @test "podman auto-update with multiple services" {
     # Preserve original image ID, to confirm that it changes (or not)
     run_podman inspect --format "{{.Id}}" $IMAGE