diff --git a/ansible/group_vars/all/kolla b/ansible/group_vars/all/kolla
index 2d1e27c662893bfa2cdb924305deb6698ee67e92..56ce7319f485cf2f479b26d342e7db45424ee3ed 100644
--- a/ansible/group_vars/all/kolla
+++ b/ansible/group_vars/all/kolla
@@ -57,7 +57,7 @@ kolla_node_custom_config_path: "{{ kolla_config_path }}/config"
 kolla_base_distro: "{{ os_distribution }}"
 
 # Kolla container image type: binary or source.
-kolla_install_type: "binary"
+kolla_install_type: "source"
 
 # Docker namespace to use for Kolla images.
 kolla_docker_namespace: "kolla"
diff --git a/doc/source/configuration/reference/kolla-ansible.rst b/doc/source/configuration/reference/kolla-ansible.rst
index 11fd0c117b05b2567a2c948918fb16588229f91f..951062943b937c6bf27af5ecb2fa5a60567d9739 100644
--- a/doc/source/configuration/reference/kolla-ansible.rst
+++ b/doc/source/configuration/reference/kolla-ansible.rst
@@ -116,7 +116,7 @@ accessed.
     Kolla base container image distribution. Default is ``centos``.
 ``kolla_install_type``
     Kolla container image type: ``binary`` or ``source``. Default is
-    ``binary``.
+    ``source``.
 ``kolla_docker_registry``
     URL of docker registry to use for Kolla images. Default is not set, in
     which case Dockerhub will be used.
diff --git a/doc/source/configuration/reference/kolla.rst b/doc/source/configuration/reference/kolla.rst
index fa3b20bb423f376ba7c976307dd8cc8eea95afc8..5a35196cf729c0aa107beb51d1c2a326ad128f4c 100644
--- a/doc/source/configuration/reference/kolla.rst
+++ b/doc/source/configuration/reference/kolla.rst
@@ -77,7 +77,7 @@ affect :ref:`Kolla Ansible configuration <configuration-kolla-ansible-global>`.
     ``debian``, or ``ubuntu``. Default is ``{{ os_distribution }}``.
 ``kolla_install_type``
     Kolla container image type: ``binary`` or ``source``. Default is
-    ``binary``.
+    ``source``.
 ``kolla_docker_namespace``
     Docker namespace to use for Kolla images. Default is ``kolla``.
 ``kolla_docker_registry``
diff --git a/etc/kayobe/kolla.yml b/etc/kayobe/kolla.yml
index b43a3b907fde245d97c22df683488705db77d0a1..30276997741b5dc5619f8a0b33c73c80a0bed143 100644
--- a/etc/kayobe/kolla.yml
+++ b/etc/kayobe/kolla.yml
@@ -65,7 +65,7 @@
 # "ubuntu". Default is {{ os_distribution }}.
 #kolla_base_distro:
 
-# Kolla container image type: binary or source. Default is 'binary'.
+# Kolla container image type: binary or source. Default is 'source'.
 #kolla_install_type:
 
 # URL of docker registry to use for Kolla images. Default is not set, in which
diff --git a/playbooks/kayobe-overcloud-base/overrides.yml.j2 b/playbooks/kayobe-overcloud-base/overrides.yml.j2
index babbf2c8cfa2386312a3be611db01062c86ed1ac..1980c2bdbfd255a918cea01c0897527a1d21ab57 100644
--- a/playbooks/kayobe-overcloud-base/overrides.yml.j2
+++ b/playbooks/kayobe-overcloud-base/overrides.yml.j2
@@ -7,7 +7,6 @@ disable_selinux_do_reboot: false
 docker_registry_mirrors:
   - "http://{{ zuul_site_mirror_fqdn }}:8082/"
 
-kolla_install_type: "{{ 'source' if ansible_distribution == 'Ubuntu' else 'binary' }}"
 kolla_docker_namespace: "openstack.kolla"
 # use the published images from a site mirror of quay.io
 kolla_docker_registry: "{{ zuul_site_mirror_fqdn }}:4447"
diff --git a/releasenotes/notes/default-source-type-b379b0f1562537dd.yaml b/releasenotes/notes/default-source-type-b379b0f1562537dd.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..5f0174667a82278e12b0e664b7cd1ebcc07c3e23
--- /dev/null
+++ b/releasenotes/notes/default-source-type-b379b0f1562537dd.yaml
@@ -0,0 +1,14 @@
+---
+upgrade:
+  - |
+    Updates the default image type to ``source``. Users wishing to build and
+    deploy ``binary`` type images should set ``kolla_install_type`` to
+    ``binary`` in ``kolla.yml``. This change is to reflect the reality that
+    source images are tested more thoroughly and we (as OpenStack community)
+    have better control over them.
+issues:
+  - |
+    Switching an existing deployment from ``binary`` to ``source`` images can
+    break Horizon, which can be resolved by flushing contents of ``memcached``
+    with ``docker restart memcached``. See `Kolla Ansible bug 1886549
+    <https://bugs.launchpad.net/kolla-ansible/+bug/1886549>`__ for details.