[saehejkang]

Type of Change

• Bug fix
• New feature
• Breaking change
• Documentation update

Motivation and Context

Closes #1400

Testing

• Tested locally
• Added/updated tests
• Added/updated docs

[jglogan]

@saehejkang Let's tackle these two PRs right after next week's release.

[jglogan]

@saehejkang see the suggestion for simplifying this change. What do you think?

[github-actions]

Code Coverage

Tier	Line Coverage
Unit	24.31%
Integration	66.13%
Combined	75.51%

[jglogan]

Local test configuration, run ./test.sh to test:

entrypoint.sh

#!/bin/sh
#
# Continuously writes random 256-byte files under /tmp/output.
#
set -eu

mkdir -p /tmp/output

while true; do
    tmpfile=$(mktemp /tmp/output/.tmp.XXXXXX)
    dd if=/dev/urandom of="$tmpfile" bs=1 count=256 2>/dev/null
    hash=$(sha256sum "$tmpfile" | awk '{print $1}')
    mv "$tmpfile" "/tmp/output/$hash"
done

Dockerfile:

FROM alpine:3.20

COPY entrypoint.sh /entrypoint.sh
RUN chmod +x /entrypoint.sh

ENTRYPOINT ["/entrypoint.sh"]

test.sh:

#!/bin/sh
#
# Build and run a container that performs continuous I/O.
# Use live export to obtain two different tar archives.
# Import these in Colima or other Docker-like and run
# to measure how many files were created.
#
set -euox pipefail

CONTAINER="${CONTAINER:-container}"
EXPORT_OPTS=${EXPORT_OPTS:-}
IMAGE=liveexport-test
NAME=liveexport-test-run

${CONTAINER} build -t "${IMAGE}" .
${CONTAINER} run -d --rm --name "${NAME}" "${IMAGE}"

trap '${CONTAINER} rm -f "${NAME}"' EXIT

sleep 2
${CONTAINER} export ${EXPORT_OPTS} -o "${NAME}-1.tar" "${NAME}"

sleep 2
${CONTAINER} export ${EXPORT_OPTS} -o "${NAME}-2.tar" "${NAME}"

docker import "${NAME}-1.tar" "${IMAGE}-1"
docker import "${NAME}-2.tar" "${IMAGE}-2"

docker run -it --rm "${IMAGE}-1" ls /tmp/output | wc -l
docker run -it --rm "${IMAGE}-2" ls /tmp/output | wc -l

[jglogan]

Test feedback, from exporting with container and docker (via Colima):

EXPORT_OPTS=--live ./test.sh
CONTAINER=docker ./test.sh

• Basic functionality looks good. With the --live flag, and for the first run, it works fine.
• Please remove the --live flag, and instead, in the RuntimeService, just use the is-running detection result to determine whether freeze/thaw is necessary. The user shouldn't have to concern themselves with the state of the container. The test should pass using ./test.sh without EXPORT_OPTS.
• container export fails on back-to-back runs because it refuses to overwrite the output file (Error: “archive.tar” couldn’t be moved to “20260801-container-liveexport” because an item with the same name already exists.). The command should overwrite the previous file without consulting the user.