diff --git a/.github/workflows/deploy_apptainer.yml b/.github/workflows/deploy_apptainer.yml
index e7b8081..1034cc3 100644
--- a/.github/workflows/deploy_apptainer.yml
+++ b/.github/workflows/deploy_apptainer.yml
@@ -20,12 +20,6 @@ jobs:
         with:
           fetch-depth: 0
 
-      - name: add apptainer source
-        shell: bash
-        run: |
-          sudo add-apt-repository -y ppa:apptainer/ppa
-          sudo apt-get update
-
       - name: create dockerfile
         uses: snakemake/snakemake-github-action@v2
         with:
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index db11319..2d5653d 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -53,4 +53,4 @@ jobs:
         with:
           directory: .test
           snakefile: workflow/Snakefile
-          args: "--report report.zip"
+          args: "--cores 2 --report report.zip"
diff --git a/workflow/Snakefile b/workflow/Snakefile
index fb02f75..38ec062 100644
--- a/workflow/Snakefile
+++ b/workflow/Snakefile
@@ -21,7 +21,7 @@ include: "rules/report.smk"
 
 # container definition (optional)
 # -----------------------------------------------------
-container: "oras://ghcr.io/mpusp/snakemake-simple-mapping:latest"
+containerized: "oras://ghcr.io/mpusp/snakemake-simple-mapping:latest"
 
 
 # optional messages, log and error handling