diff --git a/src/build.lock b/src/build.lock
new file mode 100644
index 0000000..282b03e
--- /dev/null
+++ b/src/build.lock
@@ -0,0 +1,164 @@
+{
+  "locks": [
+    {
+      "type": "layer",
+      "item": "layer:options",
+      "url": "https://github.com/juju-solutions/layer-options.git",
+      "vcs": null,
+      "branch": "refs/heads/master",
+      "commit": "fcdcea4e5de3e1556c24e6704607862d0ba00a56"
+    },
+    {
+      "type": "layer",
+      "item": "layer:basic",
+      "url": "https://github.com/juju-solutions/layer-basic.git",
+      "vcs": null,
+      "branch": "refs/heads/master",
+      "commit": "623e69c7b432456fd4364f6e1835424fd6b5425e"
+    },
+    {
+      "type": "layer",
+      "item": "layer:openstack",
+      "url": "https://github.com/openstack/charm-layer-openstack",
+      "vcs": null,
+      "branch": "refs/heads/master",
+      "commit": "ba152d41b4a1109073d335415f43c4248109e7c7"
+    },
+    {
+      "type": "layer",
+      "item": "barbican-softhsm",
+      "url": null,
+      "vcs": null,
+      "branch": "refs/heads/master",
+      "commit": "c6dcfbbdf414176f55668460ddc1af83b4ab5a6b"
+    },
+    {
+      "type": "layer",
+      "item": "interface:tls-certificates",
+      "url": "https://github.com/juju-solutions/interface-tls-certificates",
+      "vcs": null,
+      "branch": "refs/heads/master",
+      "commit": "d9850016d930a6d507b9fd45e2598d327922b140"
+    },
+    {
+      "type": "layer",
+      "item": "interface:barbican-hsm",
+      "url": "https://opendev.org/x/charm-interface-barbican-hsm",
+      "vcs": null,
+      "branch": "refs/heads/master",
+      "commit": "a2705db6a534bdc61bfac2b69f539ead165da4b9"
+    },
+    {
+      "type": "python_module",
+      "package": "charms.openstack",
+      "url": "git+https://opendev.org/openstack/charms.openstack.git",
+      "branch": "refs/heads/stable/21.04",
+      "version": "bcd0c9b4b4a19d4a4125e0a6a3f808a843a74fa1",
+      "vcs": "git"
+    },
+    {
+      "type": "python_module",
+      "package": "netaddr",
+      "vcs": null,
+      "version": "0.7.19"
+    },
+    {
+      "type": "python_module",
+      "package": "pbr",
+      "vcs": null,
+      "version": "5.5.1"
+    },
+    {
+      "type": "python_module",
+      "package": "setuptools",
+      "vcs": null,
+      "version": "41.6.0"
+    },
+    {
+      "type": "python_module",
+      "package": "Jinja2",
+      "vcs": null,
+      "version": "2.10.1"
+    },
+    {
+      "type": "python_module",
+      "package": "pip",
+      "vcs": null,
+      "version": "18.1"
+    },
+    {
+      "type": "python_module",
+      "package": "pyaml",
+      "vcs": null,
+      "version": "20.4.0"
+    },
+    {
+      "type": "python_module",
+      "package": "dnspython",
+      "vcs": null,
+      "version": "1.16.0"
+    },
+    {
+      "type": "python_module",
+      "package": "MarkupSafe",
+      "vcs": null,
+      "version": "1.1.1"
+    },
+    {
+      "type": "python_module",
+      "package": "charmhelpers",
+      "url": "git+https://github.com/juju/charm-helpers.git",
+      "branch": "refs/heads/stable/21.04",
+      "version": "8c48d2914b0e7396a2392c3933e2d7f321643ae6",
+      "vcs": "git"
+    },
+    {
+      "type": "python_module",
+      "package": "wheel",
+      "vcs": null,
+      "version": "0.33.6"
+    },
+    {
+      "type": "python_module",
+      "package": "charms.reactive",
+      "vcs": null,
+      "version": "1.4.1"
+    },
+    {
+      "type": "python_module",
+      "package": "Tempita",
+      "vcs": null,
+      "version": "0.5.2"
+    },
+    {
+      "type": "python_module",
+      "package": "PyYAML",
+      "vcs": null,
+      "version": "5.2"
+    },
+    {
+      "type": "python_module",
+      "package": "setuptools_scm",
+      "vcs": null,
+      "version": "1.17.0"
+    },
+    {
+      "type": "python_module",
+      "package": "psutil",
+      "vcs": null,
+      "version": "5.8.0"
+    },
+    {
+      "type": "python_module",
+      "package": "netifaces",
+      "vcs": null,
+      "version": "0.10.9"
+    },
+    {
+      "type": "python_module",
+      "package": "six",
+      "vcs": null,
+      "version": "1.15.0"
+    }
+  ]
+}
\ No newline at end of file
diff --git a/src/wheelhouse.txt b/src/wheelhouse.txt
index 2a8741d..10e232f 100644
--- a/src/wheelhouse.txt
+++ b/src/wheelhouse.txt
@@ -1,5 +1,5 @@
 psutil
 
-git+https://opendev.org/openstack/charms.openstack.git#egg=charms.openstack
+git+https://opendev.org/openstack/charms.openstack.git@stable/21.04#egg=charms.openstack
 
-git+https://github.com/juju/charm-helpers.git#egg=charmhelpers
+git+https://github.com/juju/charm-helpers.git@stable/21.04#egg=charmhelpers
diff --git a/test-requirements.txt b/test-requirements.txt
index 14b380e..f0d4636 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -10,4 +10,4 @@ charms.reactive
 mock>=1.2
 nose>=1.3.7
 coverage>=3.6
-git+https://github.com/openstack/charms.openstack.git#egg=charms.openstack
+git+https://github.com/openstack/charms.openstack.git@stable/21.04#egg=charms.openstack
diff --git a/tox.ini b/tox.ini
index ce79fa1..391b2af 100644
--- a/tox.ini
+++ b/tox.ini
@@ -28,7 +28,12 @@ deps =
 [testenv:build]
 basepython = python3
 commands =
-    charm-build --log-level DEBUG -o {toxinidir}/build/builds src {posargs}
+    charm-build --log-level DEBUG --use-lock-file-branches -o {toxinidir}/build/builds src {posargs}
+
+[testenv:add-build-lock-file]
+basepython = python3
+commands =
+    charm-build --log-level DEBUG --write-lock-file -o {toxinidir}/build/builds src {posargs}
 
 [testenv:py3]
 basepython = python3