diff --git a/.github/scripts/post_pr_comment.sh b/.github/scripts/post_pr_comment.sh
index 3048f6a7..4f390278 100755
--- a/.github/scripts/post_pr_comment.sh
+++ b/.github/scripts/post_pr_comment.sh
@@ -7,6 +7,15 @@ generate_post_data()
 EOF
 }
 PR_NUMBER=$(echo $GITHUB_REF | awk 'BEGIN { FS = "/" } ; { print $3 }')
+echo "github ref:" $GITHUB_REF
+echo "pr number:" $PR_NUMBER
+echo "PR number" "${PR_NUMBER2}"
+echo "PR number"  "${PR_NUMBER}"
+echo "github_repository:" "$GITHUB_REPOSITORY"
+
+PR_NUMBER=$(jq --raw-output .pull_request.number "$GITHUB_EVENT_PATH")
+echo PR_NUMBER
+#PR_NUMBER="${PR_NUMBER2}"
 curl -s -H "Authorization: token ${KEY4HEP_COMMENT_BOT_TOKEN}" \
  -X POST -d "$(generate_post_data)"  \
  "https://api.github.com/repos/${GITHUB_REPOSITORY}/issues/${PR_NUMBER}/comments"
diff --git a/.github/workflows/concretize-lxplus-pr-target.yaml b/.github/workflows/concretize-lxplus-pr-target.yaml
new file mode 100644
index 00000000..0dcc4c79
--- /dev/null
+++ b/.github/workflows/concretize-lxplus-pr-target.yaml
@@ -0,0 +1,48 @@
+name: concretize-lxplus-comment-bot
+on: [pull_request_target]
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - name: Check if workflow should be run
+      run: |
+        ismember=$(curl \
+            -o /dev/null --silent --head \
+            -H "Authorization: token ${{ secrets.COMMENT_TOKEN }}" \
+          --write-out '%{http_code}\n' \
+          https://api.github.com/orgs/key4hep/members/vvolkl\
+          )
+        if [ "$ismember" = 204 ]
+        then 
+          echo "" 
+        else
+          exit 1
+        fi
+    - uses: actions/checkout@v2
+      with:
+        ref: ${{github.event.pull_request.head.ref}}
+        repository: ${{github.event.pull_request.head.repo.full_name}}
+    - uses: cvmfs-contrib/github-action-cvmfs@v2
+      with:
+        cvmfs_repositories: 'sw.hsf.org,sw-nightlies.hsf.org,sft-nightlies.cern.ch,sft.cern.ch,geant4.cern.ch'
+    - name: Start container
+      run: |
+        docker run -it --name CI_container -e GITHUB_ENV=${GITHUB_ENV}  -v ${GITHUB_WORKSPACE}:/Package -v /cvmfs:/cvmfs:shared -d clicdp/cc7-lcg /bin/bash
+    - name: Setup container
+      run: |
+        docker exec CI_container /bin/bash -c ' ln -s /usr/lib64/liblzma.so.5.2.2 /usr/lib64/liblzma.so;'
+    - name: Setup Spack
+      run: |
+        docker exec CI_container /bin/bash -c 'cd ./Package;\
+        source scripts/ci_setup_spack2.sh;'
+    - name: Concretize
+      run: |
+        docker exec CI_container /bin/bash -c 'cd ./Package;\
+        source spack/share/spack/setup-env.sh;\
+        spack spec -I key4hep-stack | tee -a key4hep-stack-concretization.log;'
+    - name: Comment PR 
+      env:
+        KEY4HEP_COMMENT_BOT_TOKEN: ${{ secrets.KEY4HEP_COMMENT_BOT_TOKEN }}
+      run: |
+        ${GITHUB_WORKSPACE}/.github/scripts/generate_pr_comment.sh
+        ${GITHUB_WORKSPACE}/.github/scripts/post_pr_comment.sh
diff --git a/.github/workflows/concretize-lxplus.yaml b/.github/workflows/concretize-lxplus.yaml
index 87648417..9367f5c6 100644
--- a/.github/workflows/concretize-lxplus.yaml
+++ b/.github/workflows/concretize-lxplus.yaml
@@ -25,10 +25,8 @@ jobs:
         docker exec CI_container /bin/bash -c 'cd ./Package;\
         source spack/share/spack/setup-env.sh;\
         spack spec -I key4hep-stack | tee -a key4hep-stack-concretization.log;'
-    - name: Comment PR 
-      if: github.event_name == 'pull_request'
-      env:
-        KEY4HEP_COMMENT_BOT_TOKEN: ${{ secrets.KEY4HEP_COMMENT_BOT_TOKEN }}
-      run: |
-        ${GITHUB_WORKSPACE}/.github/scripts/generate_pr_comment.sh
-        ${GITHUB_WORKSPACE}/.github/scripts/post_pr_comment.sh
+    - uses: actions/upload-artifact@v2
+      with:
+        name: concretization-log-artifact
+        path: key4hep-stack-concretization.log
+        retention-days: 5
diff --git a/config/compilers_centos7_cvmfs.yaml b/config/compilers_centos7_cvmfs.yaml
new file mode 100644
index 00000000..5342c7a0
--- /dev/null
+++ b/config/compilers_centos7_cvmfs.yaml
@@ -0,0 +1,14 @@
+compilers:
+- compiler:
+    paths:
+      cc: /cvmfs/sw.hsf.org/spackages/linux-centos7-haswell/gcc-4.8.5/gcc-8.3.0-avsmzt7bekq7ispf6zlarx6vwdretbae/bin/gcc
+      cxx: /cvmfs/sw.hsf.org/spackages/linux-centos7-haswell/gcc-4.8.5/gcc-8.3.0-avsmzt7bekq7ispf6zlarx6vwdretbae/bin/g++
+      f77: /cvmfs/sw.hsf.org/spackages/linux-centos7-haswell/gcc-4.8.5/gcc-8.3.0-avsmzt7bekq7ispf6zlarx6vwdretbae/bin/gfortran
+      fc: /cvmfs/sw.hsf.org/spackages/linux-centos7-haswell/gcc-4.8.5/gcc-8.3.0-avsmzt7bekq7ispf6zlarx6vwdretbae/bin/gfortran
+    operating_system: centos7
+    target: x86_64
+    modules: []
+    environment: {}
+    extra_rpaths: []
+    flags: {}
+    spec: gcc@8.3.0
diff --git a/config/packages.yaml b/config/packages.yaml
index ac6dff9d..00a90ad3 100644
--- a/config/packages.yaml
+++ b/config/packages.yaml
@@ -2,7 +2,7 @@
 packages:
   all:
     target: [broadwell]
-    variants: build_type=Release
+    variants: build_type=Debug
     buildable: true
     version: []
     providers:
diff --git a/scripts/ci_setup_spack.sh b/scripts/ci_setup_spack.sh
index 7edfcb7e..7ce6611f 100755
--- a/scripts/ci_setup_spack.sh
+++ b/scripts/ci_setup_spack.sh
@@ -13,7 +13,7 @@
  echo ' - $SPACK_ROOT/var/spack/repos/key4hep-spack' >> spack/etc/spack/repos.yaml
  tar -czf key4hep-spack.tar.gz spack
  cp ${PWD}/spack/var/spack/repos/key4hep-spack/config/cvmfs_build/upstreams.yaml spack/etc/spack/
-# compiler setup 
+ compiler setup 
  spack load gcc
  spack compiler find --scope site
  tar -czf key4hep-spack_centos7-cvmfs.tar.gz spack
diff --git a/scripts/ci_setup_spack2.sh b/scripts/ci_setup_spack2.sh
new file mode 100755
index 00000000..ed0e74b2
--- /dev/null
+++ b/scripts/ci_setup_spack2.sh
@@ -0,0 +1,20 @@
+# set up spack inside the k4-spack repo
+ if [ -n "$SPACK_VERSION" ]; then git clone  https://github.com/key4hep/spack ; cd spack; git checkout $SPACK_VERSION; cd ..; else git clone --depth 1 https://github.com/key4hep/spack; fi 
+ source spack/share/spack/setup-env.sh
+# get the right config files to the right places
+ cp config/packages.yaml spack/etc/spack/
+ mkdir spack/var/spack/repos/key4hep-spack
+ cp -r * spack/var/spack/repos/key4hep-spack || true
+# clean up git directories for zip
+ rm -rf spack/var/spack/repos/key4hep-spack/spack || true
+ rm -rf spack/.git
+# register k4 package recipes with spack
+ echo "repos:" > spack/etc/spack/repos.yaml
+ echo ' - $SPACK_ROOT/var/spack/repos/key4hep-spack' >> spack/etc/spack/repos.yaml
+ tar -czf key4hep-spack.tar.gz spack
+ cp ${PWD}/spack/var/spack/repos/key4hep-spack/config/cvmfs_build/upstreams.yaml spack/etc/spack/
+ cp config/compilers_centos7_cvmfs.yaml spack/etc/spack/compilers.yaml
+# compiler setup 
+# spack load gcc
+# spack compiler find --scope site
+# tar -czf key4hep-spack_centos7-cvmfs.tar.gz spack