Replace existing virt-customize usage with tripleo-mount-image

The `tripleo-mount-image` tool was created as an alternative for
kpartx-based customizations which do not support the multiple mount
points of overcloud-hardened-uefi-full.qcow2.

virt-customize sets a machine-id in the image, which results in all
overcloud nodes having the same machine-id [1]. virt-customize can
also be very slow on virtualized underclouds.

This change replaces virt-customize usage with
tripleo-mount-image+chroot as the recommended tool for overcloud image
customizations.

[1] https://bugzilla.redhat.com/show_bug.cgi?id=1554546

Change-Id: I3f65479777cc3dfa1ed3c396dbfbe182288ae65b

deploy-guide/source/deployment/3rd_party.rst

@@ -370,18 +370,28 @@ kernel module is deployed on the host
 .....................................
 
 The kernel module is deployed on the base Operating System via RPM or DKMS.
-It is suggested to deploy the module via virt-customize.
-The libguestfs-tools package contains the virt-customize tool. Install the libguestfs-tools::
+Deploy the module by using the ``tripleo-mount-image`` tool and create a
+``chroot``.
 
-    sudo yum install libguestfs-tools
+First you need to create a repository file where the module will be downloaded from, and copy the repo file into the image::
 
-Then you need to create a repository file where the module will be downloaded from, and uplaod the repo into the image::
+    temp_dir=$(mktemp -d)
+    sudo tripleo-mount-image -a /path/to/overcloud-full.qcow2 -m $temp_dir
+    sudo cp my-repo.repo $temp_dir/etc/yum.repos.d/
 
-    virt-customize --selinux-relabel -a overcloud-full.qcow2 --upload my-repo.repo:/etc/yum.repos.d/
+You can now start a chroot and install the rpm that contains the kernel module::
 
-Once the repository is deployed, you can now install the rpm that contains the kernel module::
+    sudo mount -o bind /dev $temp_dir/dev/
+    sudo cp /etc/resolv.conf $temp_dir/etc/resolv.conf
+    sudo chroot $temp_dir /bin/bash
+    dnf install my-rpm
+    exit
 
-    virt-customize --selinux-relabel -a overcloud-full.qcow2 --install my-rpm
+Then unmount the image::
+
+    sudo rm $temp_dir/etc/resolv.conf
+    sudo umount $temp_dir/dev
+    sudo tripleo-unmount-image -m $temp_dir
 
 Now that the rpm is deployed with the kernel module, we need to configure TripleO to load it.
 To configure an extra kernel module named "dpdk_module" for a specific role, we would add::

deploy-guide/source/features/ops_tools.rst

@@ -71,20 +71,25 @@ Before deploying the Overcloud
 
 1. Install client packages on overcloud-full image:
 
-   - Prepare installation script::
+   - Mount the image and create a chroot::
 
-      cat >install.sh<<EOF
-      #!/usr/bin/sh
-      yum install -y centos-release-opstools
-      yum install -y sensu fluentd collectd
-      EOF
+      temp_dir=$(mktemp -d)
+      sudo tripleo-mount-image -a /path/to/overcloud-full.qcow2 -m $temp_dir
+      sudo mount -o bind /dev $temp_dir/dev/
+      sudo cp /etc/resolv.conf $temp_dir/etc/resolv.conf
+      sudo chroot $temp_dir /bin/bash
 
-   - Run the script using virt-customize::
+   - Install the packages inside the chroot::
 
-      LIBGUESTFS_BACKEND=direct virt-customize -a /path/to/overcloud-full.qcow2 \
-        --upload install.sh:/tmp/install.sh \
-        --run-command "sh /tmp/install.sh" \
-        --selinux-relabel
+      dnf install -y centos-release-opstools
+      dnf install -y sensu fluentd collectd
+      exit
+
+   - Unmount the image::
+
+      sudo rm $temp_dir/etc/resolv.conf
+      sudo umount $temp_dir/dev
+      sudo tripleo-unmount-image -m $temp_dir
 
    - Upload new image to undercloud image registry::