diff --git a/api-guide/source/conf.py b/api-guide/source/conf.py
index 5ced3d297365..7373c3c00ed1 100644
--- a/api-guide/source/conf.py
+++ b/api-guide/source/conf.py
@@ -88,7 +88,7 @@ gitsha = subprocess.Popen(
 
 # source tree
 pwd = subprocess.Popen(
-    "pwd", stdout=subprocess.PIPE).communicate()[0].strip('\n')
+    "pwd", stdout=subprocess.PIPE).communicate()[0].decode().strip('\n')
 
 # html_context allows us to pass arbitrary values into the html template
 html_context = {"pwd": pwd,
diff --git a/api-ref/source/conf.py b/api-ref/source/conf.py
index c5960b86dbe5..aa3d96725330 100644
--- a/api-ref/source/conf.py
+++ b/api-ref/source/conf.py
@@ -148,7 +148,7 @@ git_cmd = ["git", "log", "--pretty=format:'%ad, commit %h'", "--date=local",
     "-n1"]
 try:
     html_last_updated_fmt = subprocess.Popen(
-        git_cmd, stdout=subprocess.PIPE).communicate()[0]
+        git_cmd, stdout=subprocess.PIPE).communicate()[0].decode()
 except Exception:
     warnings.warn('Cannot get last updated time from git repository. '
                   'Not setting "html_last_updated_fmt".')
diff --git a/doc/ext/support_matrix.py b/doc/ext/support_matrix.py
index 67e9b44dfb2a..afcfe87941c3 100644
--- a/doc/ext/support_matrix.py
+++ b/doc/ext/support_matrix.py
@@ -317,7 +317,7 @@ class SupportMatrixDirective(rst.Directive):
         summaryhead.append(header)
 
         # then one column for each hypervisor driver
-        impls = matrix.targets.keys()
+        impls = list(matrix.targets.keys())
         impls.sort()
         for key in impls:
             target = matrix.targets[key]
@@ -350,7 +350,7 @@ class SupportMatrixDirective(rst.Directive):
                 classes=["sp_feature_" + feature.status]))
 
             # and then one column for each hypervisor driver
-            impls = matrix.targets.keys()
+            impls = list(matrix.targets.keys())
             impls.sort()
             for key in impls:
                 target = matrix.targets[key]
diff --git a/doc/source/conf.py b/doc/source/conf.py
index dce5004ad976..e3cd90d4da8b 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -197,7 +197,7 @@ git_cmd = ["git", "log", "--pretty=format:'%ad, commit %h'", "--date=local",
     "-n1"]
 try:
     html_last_updated_fmt = subprocess.Popen(
-        git_cmd, stdout=subprocess.PIPE).communicate()[0]
+        git_cmd, stdout=subprocess.PIPE).communicate()[0].decode()
 except Exception:
     warnings.warn('Cannot get last updated time from git repository. '
                   'Not setting "html_last_updated_fmt".')