IGNITE-29164 [ducktests] Support rootless Docker in the local runner

modules/ducktests/README.md

@@ -19,7 +19,7 @@ All paths below are relative to `${IGNITE_HOME}/modules/ducktests/tests`:
 Docker is used to emulate a distributed multi-node cluster environment where each individual container acts as a running cluster node.
 
 ### 1. Prerequisites
-* **Docker** installed and running on your host system.
+* **Docker** installed and running on your host system. A rootless daemon works too: the runner detects it and runs the `ducker` user as container root, which the daemon maps to you. Network fault tests then need the `iptables` and `sch_netem` kernel modules already loaded on the host, since a rootless container cannot load them.
 * **Python >= 3.8** installed on your host system (required only for local environment scripts and development).
 
 ### 2. Prepare the Environment & Code

modules/ducktests/tests/docker/Dockerfile

@@ -170,8 +170,9 @@ ARG USER_GID=1000
 RUN getent passwd ubuntu &>/dev/null && userdel -r ubuntu || true
 
 # Provision ducker system environment and security configurations
-RUN groupadd -g $USER_GID ducker \
-    && useradd -u $USER_UID -g $USER_GID -ms /bin/bash ducker \
+# -o lets ducker share uid and gid 0 with root in an image built for a rootless daemon (see ducker-ignite).
+RUN groupadd -o -g $USER_GID ducker \
+    && useradd -o -u $USER_UID -g $USER_GID -ms /bin/bash ducker \
     && mkdir -p /home/ducker/ \
     && rsync -aiq /root/.ssh/ /home/ducker/.ssh \
     && chown -R ducker /home/ducker/ /mnt/ /var/log/ /opt \

modules/ducktests/tests/docker/ducker-ignite

@@ -267,6 +267,17 @@ ducker_build_image() {
         extra_build_args="--no-cache"
     fi
 
+    # The ducker user must be able to write the checkout that ducker_run mounts. A rootless daemon
+    # maps only container root to the caller, so there ducker is built as uid 0.
+    local ducker_uid="$(id -u)"
+    local ducker_gid="$(id -g)"
+
+    if docker info --format '{{.SecurityOptions}}' 2>/dev/null | grep -q rootless; then
+        echo "** Rootless Docker detected: building ducker as uid 0."
+        ducker_uid=0
+        ducker_gid=0
+    fi
+
     # Use SECONDS, a builtin bash variable that gets incremented each second, to measure the docker
     # build duration.
     SECONDS=0
@@ -275,7 +286,7 @@ ducker_build_image() {
     # Tip: if you are scratching your head for some dependency problems that are referring to an old code version
     # (for example java.lang.NoClassDefFoundError), add --no-cache flag to the build shall give you a clean start.
     must_do -v -o docker build ${extra_build_args} --network=host --memory="${docker_build_memory_limit}" \
-        --build-arg USER_UID=$(id -u) --build-arg USER_GID=$(id -g) \
+        --build-arg USER_UID=${ducker_uid} --build-arg USER_GID=${ducker_gid} \
         --build-arg "ducker_creator=${user_name}" --build-arg "jdk_version=${jdk_version}" \
         --build-arg "python_version=${python_version}" -t "${image_name}" \
         -f "${docker_context}/Dockerfile" -- "${docker_context}"