diff --git a/libvirt-qemu/README.md b/libvirt-qemu/README.md
index e42c26e872925a1e9d99f6c72257d9261c259f9b..5f440a982fc157da0d77dce0f12ab8f1b7762938 100644
--- a/libvirt-qemu/README.md
+++ b/libvirt-qemu/README.md
@@ -89,15 +89,6 @@ libvirt domains (over SSH).
   redirects COM1 to a file which can be inspected on the host in case of
   boot issues.
 
-- [GitLab Runner Docker executor][3] uses the `image` keyword for
-  determining which Docker image to use.  The contents of that keyword
-  are not exposed as an environment variable by the [GitLab Runner
-  Custom executor][4] and thus it cannot be used for determining the
-  operating system image to use.  Instead, the latter is extracted from
-  the job name.  The QCOW2 image file path is derived from the detected
-  operating system name and release (see the `do_prepare()` function in
-  `executor.sh` for hints on expected file naming).
-
 ## QCOW2 Image Synchronization
 
 Whenever [GitLab Runner Docker executor][3] runs a GitLab CI job, it
diff --git a/libvirt-qemu/executor.sh b/libvirt-qemu/executor.sh
index 0b1a8230224a7fdf94b8630e82649ab127752934..ed5688a72090e9ed4b70db3fbb9cb400de3f440b 100755
--- a/libvirt-qemu/executor.sh
+++ b/libvirt-qemu/executor.sh
@@ -18,10 +18,6 @@ CONFIG_PATH="/etc/gitlab-runner/executor-libvirt-qemu.conf"
 # shellcheck source=executor.conf.sample
 . "${CONFIG_PATH}"
 
-CENTOS_RELEASE="$(expr "${CUSTOM_ENV_CI_JOB_NAME}" : ".*:el\([6-8]\)\(:\|$\)" || :)"
-OPENBSD_RELEASE="$(expr "${CUSTOM_ENV_CI_JOB_NAME}" : ".*:openbsd\([0-9][0-9.]*\)\(:\|$\)" || :)"
-FREEBSD_RELEASE="$(expr "${CUSTOM_ENV_CI_JOB_NAME}" : ".*:freebsd\([0-9][0-9.]*\)\(:\|$\)" || :)"
-
 BASE_IMAGE_DIR="${BASE_DIR}/qcow2"
 RUNNER_NAME="runner-${CUSTOM_ENV_CI_JOB_ID}"
 DOMAIN_DEFINITION_PATH="${BASE_DIR}/${RUNNER_NAME}.xml"
@@ -50,18 +46,9 @@ do_config() {
 }
 
 do_prepare() {
-	if [ -n "${CENTOS_RELEASE}" ]; then
-		BASE_IMAGE_PATH="$(readlink -f "${BASE_IMAGE_DIR}/centos-${CENTOS_RELEASE}-x86_64")"
-	elif [ -n "${FREEBSD_RELEASE}" ]; then
-		BASE_IMAGE_PATH="$(readlink -f "${BASE_IMAGE_DIR}/freebsd-${FREEBSD_RELEASE}-x86_64")"
-	elif [ -n "${OPENBSD_RELEASE}" ]; then
-		BASE_IMAGE_PATH="$(readlink -f "${BASE_IMAGE_DIR}/openbsd-${OPENBSD_RELEASE}-x86_64")"
-	else
-		fatal_error "Unable to extract OS to use from job name (${CUSTOM_ENV_CI_JOB_NAME})"
-	fi
-
+	BASE_IMAGE_PATH="$(readlink -f "${BASE_IMAGE_DIR}/${CUSTOM_ENV_CI_JOB_IMAGE}")"
 	if [ ! -f "${BASE_IMAGE_PATH}" ]; then
-		fatal_error "Base image ${BASE_IMAGE_PATH} does not exist"
+		fatal_error "Base image ${CUSTOM_ENV_CI_JOB_IMAGE} does not exist"
 	fi
 
 	cp "${DOMAIN_DEFINITION_TEMPLATE_PATH}" "${DOMAIN_DEFINITION_PATH}"