diff --git a/doc/design-2.2.rst b/doc/design-2.2.rst
index 87a268aa9c87218bc5b9790c7dc52e858ec72dbb..66f13b020807786b2b895579d1c526ead468efa5 100644
--- a/doc/design-2.2.rst
+++ b/doc/design-2.2.rst
@@ -720,7 +720,7 @@ These lists will be modifiable via ``gnt-os modify`` (implemented via
 preseeded into a given state.
 
 For the hidden OSes, they are fully functional except that they are not
-returned in the default OS list (as computed via ``OpDiagnoseOS``),
+returned in the default OS list (as computed via ``OpOsDiagnose``),
 unless the hidden state is requested.
 
 For the blacklisted OSes, they are also not shown (unless the
diff --git a/lib/client/gnt_instance.py b/lib/client/gnt_instance.py
index 23a2e64cb82dfa233226aa79cd4759985490aaf9..7f12d9252ef7255bd7d210955120f2a9cddc0061 100644
--- a/lib/client/gnt_instance.py
+++ b/lib/client/gnt_instance.py
@@ -458,7 +458,7 @@ def ReinstallInstance(opts, args):
 
   # second, if requested, ask for an OS
   if opts.select_os is True:
-    op = opcodes.OpDiagnoseOS(output_fields=["name", "variants"], names=[])
+    op = opcodes.OpOsDiagnose(output_fields=["name", "variants"], names=[])
     result = SubmitOpCode(op, opts=opts)
 
     if not result:
diff --git a/lib/client/gnt_os.py b/lib/client/gnt_os.py
index 3095a9e357e2ef13770de5879afa6cee107235df..4241e34f994a1f779d68360162cdfa29bf30f2e4 100644
--- a/lib/client/gnt_os.py
+++ b/lib/client/gnt_os.py
@@ -42,7 +42,7 @@ def ListOS(opts, args):
   @return: the desired exit code
 
   """
-  op = opcodes.OpDiagnoseOS(output_fields=["name", "variants"], names=[])
+  op = opcodes.OpOsDiagnose(output_fields=["name", "variants"], names=[])
   result = SubmitOpCode(op, opts=opts)
 
   if not result:
@@ -77,7 +77,7 @@ def ShowOSInfo(opts, args):
   @return: the desired exit code
 
   """
-  op = opcodes.OpDiagnoseOS(output_fields=["name", "valid", "variants",
+  op = opcodes.OpOsDiagnose(output_fields=["name", "valid", "variants",
                                            "parameters", "api_versions",
                                            "blacklisted", "hidden"],
                             names=[])
@@ -146,7 +146,7 @@ def DiagnoseOS(opts, args):
   @return: the desired exit code
 
   """
-  op = opcodes.OpDiagnoseOS(output_fields=["name", "valid", "variants",
+  op = opcodes.OpOsDiagnose(output_fields=["name", "valid", "variants",
                                            "node_status", "hidden",
                                            "blacklisted"], names=[])
   result = SubmitOpCode(op, opts=opts)
diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index 8298ad549da994d362eb6362f372da1ff0ce4c43..f8a02bdd584bbc26febc45de75ac143e821de953 100644
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -3295,7 +3295,7 @@ class LUOobCommand(NoHooksLU):
 
 
 
-class LUDiagnoseOS(NoHooksLU):
+class LUOsDiagnose(NoHooksLU):
   """Logical unit for OS diagnose/query.
 
   """
diff --git a/lib/opcodes.py b/lib/opcodes.py
index 027b26519539f7e4391bc498ef0a7c729bf2965b..d0c0ef448fde433ca3498366c5e6701a6d0a3a74 100644
--- a/lib/opcodes.py
+++ b/lib/opcodes.py
@@ -1079,7 +1079,7 @@ class OpGroupRename(OpCode):
 
 
 # OS opcodes
-class OpDiagnoseOS(OpCode):
+class OpOsDiagnose(OpCode):
   """Compute the list of guest operating systems."""
   OP_ID = "OP_OS_DIAGNOSE"
   OP_PARAMS = [
diff --git a/lib/rapi/rlib2.py b/lib/rapi/rlib2.py
index db1c357c547ca746caf3837be53a7aa1991c9767..1f95bcb224e47155c0c56aa124f9a6716d254f4a 100644
--- a/lib/rapi/rlib2.py
+++ b/lib/rapi/rlib2.py
@@ -160,7 +160,7 @@ class R_2_os(baserlib.R_Generic):
 
     """
     cl = baserlib.GetClient()
-    op = opcodes.OpDiagnoseOS(output_fields=["name", "variants"], names=[])
+    op = opcodes.OpOsDiagnose(output_fields=["name", "variants"], names=[])
     job_id = baserlib.SubmitJob([op], cl)
     # we use custom feedback function, instead of print we log the status
     result = cli.PollJob(job_id, cl, feedback_fn=baserlib.FeedbackFn)
diff --git a/tools/burnin b/tools/burnin
index c55a5699c0fb73867fa4cfc0e821c6b6a9364d94..ba515751c98a9444fca74ae1ffa5bff3131236d2 100755
--- a/tools/burnin
+++ b/tools/burnin
@@ -510,7 +510,7 @@ class Burner(object):
       Err(msg, exit_code=err_code)
     self.nodes = [data[0] for data in result if not (data[1] or data[2])]
 
-    op_diagnose = opcodes.OpDiagnoseOS(output_fields=["name",
+    op_diagnose = opcodes.OpOsDiagnose(output_fields=["name",
                                                       "variants",
                                                       "hidden"],
                                        names=[])