diff --git a/Dockerfile b/Dockerfile
index 0ce51e2..130dd12 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -17,6 +17,7 @@ ENV KAL_SHLIB_ARRAY_VERSION="0.2.0" \
     KAL_SHLIB_CONFIG_VERSION="0.0.2" \
     KAL_SHLIB_CORE_VERSION="0.7.0" \
     KAL_SHLIB_FIREWALL_VERSION="0.2.0" \
+    KAL_SHLIB_DOCKER_VERSION="0.0.1" \
     KAL_SHLIB_OTHER_VERSION="0.2.2" \
     KAL_SHLIB_PRETTY_VERSION="0.4.3"
 
@@ -41,7 +42,7 @@ RUN mkdir -p /tmp/docker \
 RUN apk --update add binutils && \
     mkdir /tmp/kal-shlibs && cd /tmp/kal-shlibs && \
     export pkg && \
-    for pkg in core common array cache charm cmdline config firewall other pretty; do \
+    for pkg in core common array cache charm cmdline config firewall other pretty docker; do \
         echo "Installing kal-shlib-$pkg" ; \
         bash -c -- 'eval curl -L http://deb.kalysto.org/pool/no-dist/kal-alpha/kal-shlib-${pkg}_\${KAL_SHLIB_${pkg^^}_VERSION}-1_all.deb' > pkg.deb || exit 1 ; \
         ar x pkg.deb || exit 1; \
@@ -65,6 +66,10 @@ RUN curl -L https://git.0k.io/0k-charm.git/plain/bin/charm > /usr/local/bin/char
 RUN curl -L https://git.0k.io/git-sub.git/plain/bin/git-sub > /usr/local/bin/git-sub && \
     chmod +x /usr/local/bin/git-sub
 
+RUN curl -L https://git.0k.io/0k-docker.git/plain/src/bin/dupd > /usr/local/bin/dupd && \
+    chmod +x /usr/local/bin/dupd
+
+
 RUN curl http://docker.0k.io/get/ca.0k.io.pem > /usr/local/share/ca-certificates/ca.0k.io.pem
 
 ##force install pyyaml with libyaml
@@ -79,6 +84,7 @@ RUN cd /tmp && \
 FROM common
 
 COPY --from=builder /etc/shlib /etc/shlib
+COPY --from=builder /usr/bin/bash-shlib /usr/bin/bash-shlib
 COPY --from=builder /usr/lib/shlib /usr/lib/shlib
 COPY --from=builder /usr/local /usr/local
 
diff --git a/bin/compose-core b/bin/compose-core
index b0c0cbb..d00ea9a 100755
--- a/bin/compose-core
+++ b/bin/compose-core
@@ -352,14 +352,9 @@ export -f docker_has_image
 
 
 docker_image_id() {
-    local image="$1" image_id cache_file="$state_dir/$FUNCNAME.cache.$(echo "$*" | md5_compat)"
-    if [ -e "$cache_file" ]; then
-        # debug "$FUNCNAME: cache hit ($*)"
-        quick_cat_stdin < "$cache_file"
-        return 0
-    fi
+    local image="$1"
     image_id=$(docker inspect "$image" --format='{{.Id}}') || return 1
-    echo "$image_id" | tee "$cache_file"
+    echo "$image_id" # | tee "$cache_file"
 }
 export -f docker_image_id
 
@@ -407,6 +402,53 @@ cached_cmd_on_base_image() {
 export -f cached_cmd_on_base_image
 
 
+docker_update() {
+    ## YYY: warning, we a storing important information in cache, cache can
+    ## be removed.
+
+    ## We want here to cache the last script on given service whatever that script was
+    local service="$1" script="$2" cache_file="$CACHEDIR/$FUNCNAME.cache.$1" \
+          previous_base_image stored_image_id
+    shift
+    shift
+    ## this will build it if necessary
+    base_image=$(service_base_docker_image "$service") || return 1
+
+    ## XXXvlab: there are probably ways to avoid rebuilding that each time
+    image_id="$(docker_image_id "$base_image")" || return 1
+
+    if [ -e "$cache_file" ]; then
+        info "Cache file exists"
+        read-0 previous_base_image stored_image_id < <(cat "$cache_file")
+        info "previous: $previous_base_image"
+        info "stored: $stored_image_id"
+    else
+        info "No cache file $cache_file"
+        previous_base_image=""
+    fi
+    if [ "$previous_base_image" -a "$stored_image_id" == "$image_id" ]; then
+        info "Resetting $base_image to $previous_base_image"
+        docker tag "$previous_base_image" "$base_image" || return 1
+        image_id="$(docker_image_id "$base_image")" || return 1
+    else
+        previous_base_image="$image_id"
+    fi
+    info "Updating base image: $base_image (hash: $image_id)"
+    echo "$script" | dupd --debug -u "$base_image" -- "$@" || {
+        err "Failed updating base image"
+        return 1
+    }
+    new_image_id="$(docker_image_id "$base_image")"
+    [ "$new_image_id" == "$previous_base_image" ] && {
+        err "Image was not updated correctly (same id)."
+        return 1
+    }
+    printf "%s\0" "$previous_base_image" "$new_image_id" > "$cache_file"
+    info "Wrote cache file $cache_file"
+}
+export -f docker_update
+
+
 image_exposed_ports_0() {
     local image="$1"
     docker inspect --format='{{range $p, $conf := .Config.ExposedPorts}}{{$p}}{{"\x00"}}{{end}}' "$image"