For Yii applications, the assets and protected/runtime folders are special. First, both folders must exist and writable by the server (httpd) process. Second, these two folders contains temporary files, and should be ignored by git. If these temporary files got committed, deployment in plain servers (not Openshift servers) would cause git merge conflicts. So I put these two folders in .gitignore :
php/assets/
php/protected/runtime/
In my deployment, I add a shell script to be called by openshift, creating both folders under $OPENSHIFT_DATA_DIR and creating symbolic link to both of them in the application's folders. This is the content of the shell script (.openshift/action_hooks/deploy) which I adapted from here :
#!/bin/bash
if [ ! -d $OPENSHIFT_DATA_DIR/runtime ]; then
mkdir $OPENSHIFT_DATA_DIR/runtime
fi
# remove symlink if already exists, fix problem when with gears > 1 and nodes > 1
rm $OPENSHIFT_REPO_DIR/php/protected/runtime
ln -sf $OPENSHIFT_DATA_DIR/runtime $OPENSHIFT_REPO_DIR/php/protected/runtime
if [ ! -d $OPENSHIFT_DATA_DIR/assets ]; then
mkdir $OPENSHIFT_DATA_DIR/assets
fi
rm $OPENSHIFT_REPO_DIR/php/assets
ln -sf $OPENSHIFT_DATA_DIR/assets $OPENSHIFT_REPO_DIR/php/assets
The shell script ensures the temporary folders created on each gear after openshift deployment. By default, a new directory's right are u+rwx, and it became writable by the httpd process because the gear runs httpd as the gear user (not apache or something else).