define install root dir in CLI config

Author: plexoos

Dockerfile

@@ -64,6 +64,7 @@ COPY --chmod=0755 <<-"EOF" dostarenv.sh
 	spack compiler add $(dirname $(which gcc))
 	spack mirror add --scope site spack-buildcache file:///spack-buildcache || true
 	spack mirror list
+	spack config add 'config:install_tree:root:/opt/software'
 	spack env remove -y ${1} || true
 	spack env create ${1} /star-spack/environments/${1}.yaml
 	spack env activate ${1}
@@ -73,12 +74,6 @@ COPY --chmod=0755 <<-"EOF" dostarenv.sh
 	spack env deactivate
 EOF
 
-COPY <<"EOF" /root/.spack/config.yaml
-config:
-  install_tree:
-    root: /opt/software
-EOF
-
 RUN --mount=type=cache,target=/spack-buildcache ./dostarenv.sh star-loose
 RUN --mount=type=cache,target=/spack-buildcache ./dostarenv.sh ${starenv}
 # Load only the umbrella star-env module