tox: bump the pylint version to 2.6.0 in the default run (#544)

Changes:

tox: bump the pylint version to 2.6.0 in the default run
Fix pylint 2.6.0 W0707 warnings (raise-missing-from)

31 files changed, 154 insertions, 104 deletions

diff --git a/cloudinit/analyze/show.py b/cloudinit/analyze/show.py
index 0c825b23..01a4d3e5 100644
--- a/cloudinit/analyze/show.py
+++ b/cloudinit/analyze/show.py
@@ -267,7 +267,7 @@ def gather_timestamps_using_systemd():
                 except OSError as err:
                     raise RuntimeError('Could not determine container boot '
                                        'time from /proc/1/cmdline. ({})'
-                                       .format(err))
+                                       .format(err)) from err
                 status = CONTAINER_CODE
             else:
                 status = FAIL_CODE
diff --git a/cloudinit/cmd/devel/make_mime.py b/cloudinit/cmd/devel/make_mime.py
index 77e10540..4e6a5778 100755
--- a/cloudinit/cmd/devel/make_mime.py
+++ b/cloudinit/cmd/devel/make_mime.py
@@ -22,8 +22,10 @@ def file_content_type(text):
     try:
         filename, content_type = text.split(":", 1)
         return (open(filename, 'r'), filename, content_type.strip())
-    except ValueError:
-        raise argparse.ArgumentError(text, "Invalid value for %r" % (text))
+    except ValueError as e:
+        raise argparse.ArgumentError(
+            text, "Invalid value for %r" % (text)
+        ) from e
 
 
 def get_parser(parser=None):
diff --git a/cloudinit/config/cc_disk_setup.py b/cloudinit/config/cc_disk_setup.py
index d957cfe3..a7bdc703 100644
--- a/cloudinit/config/cc_disk_setup.py
+++ b/cloudinit/config/cc_disk_setup.py
@@ -251,7 +251,9 @@ def enumerate_disk(device, nodeps=False):
     try:
         info, _err = subp.subp(lsblk_cmd)
     except Exception as e:
-        raise Exception("Failed during disk check for %s\n%s" % (device, e))
+        raise Exception(
+            "Failed during disk check for %s\n%s" % (device, e)
+        ) from e
 
     parts = [x for x in (info.strip()).splitlines() if len(x.split()) > 0]
 
@@ -313,7 +315,9 @@ def check_fs(device):
     try:
         out, _err = subp.subp(blkid_cmd, rcs=[0, 2])
     except Exception as e:
-        raise Exception("Failed during disk check for %s\n%s" % (device, e))
+        raise Exception(
+            "Failed during disk check for %s\n%s" % (device, e)
+        ) from e
 
     if out:
         if len(out.splitlines()) == 1:
@@ -428,8 +432,8 @@ def get_dyn_func(*args):
         else:
             return globals()[func_name]
 
-    except KeyError:
-        raise Exception("No such function %s to call!" % func_name)
+    except KeyError as e:
+        raise Exception("No such function %s to call!" % func_name) from e
 
 
 def get_hdd_size(device):
@@ -437,7 +441,7 @@ def get_hdd_size(device):
         size_in_bytes, _ = subp.subp([BLKDEV_CMD, '--getsize64', device])
         sector_size, _ = subp.subp([BLKDEV_CMD, '--getss', device])
     except Exception as e:
-        raise Exception("Failed to get %s size\n%s" % (device, e))
+        raise Exception("Failed to get %s size\n%s" % (device, e)) from e
 
     return int(size_in_bytes) / int(sector_size)
 
@@ -455,8 +459,9 @@ def check_partition_mbr_layout(device, layout):
     try:
         out, _err = subp.subp(prt_cmd, data="%s\n" % layout)
     except Exception as e:
-        raise Exception("Error running partition command on %s\n%s" % (
-                        device, e))
+        raise Exception(
+            "Error running partition command on %s\n%s" % (device, e)
+        ) from e
 
     found_layout = []
     for line in out.splitlines():
@@ -485,8 +490,9 @@ def check_partition_gpt_layout(device, layout):
     try:
         out, _err = subp.subp(prt_cmd, update_env=LANG_C_ENV)
     except Exception as e:
-        raise Exception("Error running partition command on %s\n%s" % (
-                        device, e))
+        raise Exception(
+            "Error running partition command on %s\n%s" % (device, e)
+        ) from e
 
     out_lines = iter(out.splitlines())
     # Skip header.  Output looks like:
@@ -657,8 +663,10 @@ def purge_disk(device):
             try:
                 LOG.info("Purging filesystem on /dev/%s", d['name'])
                 subp.subp(wipefs_cmd)
-            except Exception:
-                raise Exception("Failed FS purge of /dev/%s" % d['name'])
+            except Exception as e:
+                raise Exception(
+                    "Failed FS purge of /dev/%s" % d['name']
+                ) from e
 
     purge_disk_ptable(device)
 
@@ -700,7 +708,9 @@ def exec_mkpart_mbr(device, layout):
     try:
         subp.subp(prt_cmd, data="%s\n" % layout)
     except Exception as e:
-        raise Exception("Failed to partition device %s\n%s" % (device, e))
+        raise Exception(
+            "Failed to partition device %s\n%s" % (device, e)
+        ) from e
 
     read_parttbl(device)
 
@@ -997,6 +1007,6 @@ def mkfs(fs_cfg):
     try:
         subp.subp(fs_cmd, shell=shell)
     except Exception as e:
-        raise Exception("Failed to exec of '%s':\n%s" % (fs_cmd, e))
+        raise Exception("Failed to exec of '%s':\n%s" % (fs_cmd, e)) from e
 
 # vi: ts=4 expandtab
diff --git a/cloudinit/config/cc_growpart.py b/cloudinit/config/cc_growpart.py
index c5d93f81..237c3d02 100644
--- a/cloudinit/config/cc_growpart.py
+++ b/cloudinit/config/cc_growpart.py
@@ -148,14 +148,14 @@ class ResizeGrowPart(object):
             if e.exit_code != 1:
                 util.logexc(LOG, "Failed growpart --dry-run for (%s, %s)",
                             diskdev, partnum)
-                raise ResizeFailedException(e)
+                raise ResizeFailedException(e) from e
             return (before, before)
 
         try:
             subp.subp(["growpart", diskdev, partnum])
         except subp.ProcessExecutionError as e:
             util.logexc(LOG, "Failed: growpart %s %s", diskdev, partnum)
-            raise ResizeFailedException(e)
+            raise ResizeFailedException(e) from e
 
         return (before, get_size(partdev))
 
@@ -187,14 +187,14 @@ class ResizeGpart(object):
         except subp.ProcessExecutionError as e:
             if e.exit_code != 0:
                 util.logexc(LOG, "Failed: gpart recover %s", diskdev)
-                raise ResizeFailedException(e)
+                raise ResizeFailedException(e) from e
 
         before = get_size(partdev)
         try:
             subp.subp(["gpart", "resize", "-i", partnum, diskdev])
         except subp.ProcessExecutionError as e:
             util.logexc(LOG, "Failed: gpart resize -i %s %s", partnum, diskdev)
-            raise ResizeFailedException(e)
+            raise ResizeFailedException(e) from e
 
         # Since growing the FS requires a reboot, make sure we reboot
         # first when this module has finished.
diff --git a/cloudinit/config/cc_power_state_change.py b/cloudinit/config/cc_power_state_change.py
index ab953a0d..6fcb8a7d 100644
--- a/cloudinit/config/cc_power_state_change.py
+++ b/cloudinit/config/cc_power_state_change.py
@@ -196,10 +196,11 @@ def load_power_state(cfg, distro_name):
 
     try:
         delay = convert_delay(delay, fmt=fmt, scale=scale)
-    except ValueError:
+    except ValueError as e:
         raise TypeError(
             "power_state[delay] must be 'now' or '+m' (minutes)."
-            " found '%s'." % delay)
+            " found '%s'." % delay
+        ) from e
 
     args = command + [delay]
     if message:
@@ -207,9 +208,10 @@ def load_power_state(cfg, distro_name):
 
     try:
         timeout = float(pstate.get('timeout', 30.0))
-    except ValueError:
-        raise ValueError("failed to convert timeout '%s' to float." %
-                         pstate['timeout'])
+    except ValueError as e:
+        raise ValueError(
+            "failed to convert timeout '%s' to float." % pstate['timeout']
+        ) from e
 
     condition = pstate.get("condition", True)
     if not isinstance(condition, (str, list, bool)):
diff --git a/cloudinit/config/cc_rsyslog.py b/cloudinit/config/cc_rsyslog.py
index 1354885a..2a2bc931 100644
--- a/cloudinit/config/cc_rsyslog.py
+++ b/cloudinit/config/cc_rsyslog.py
@@ -347,8 +347,10 @@ class SyslogRemotesLine(object):
         if self.port:
             try:
                 int(self.port)
-            except ValueError:
-                raise ValueError("port '%s' is not an integer" % self.port)
+            except ValueError as e:
+                raise ValueError(
+                    "port '%s' is not an integer" % self.port
+                ) from e
 
         if not self.addr:
             raise ValueError("address is required")
diff --git a/cloudinit/config/cc_set_hostname.py b/cloudinit/config/cc_set_hostname.py
index c13020d8..1d23d80d 100644
--- a/cloudinit/config/cc_set_hostname.py
+++ b/cloudinit/config/cc_set_hostname.py
@@ -85,7 +85,7 @@ def handle(name, cfg, cloud, log, _args):
     except Exception as e:
         msg = "Failed to set the hostname to %s (%s)" % (fqdn, hostname)
         util.logexc(log, msg)
-        raise SetHostnameError("%s: %s" % (msg, e))
+        raise SetHostnameError("%s: %s" % (msg, e)) from e
     write_json(prev_fn, {'hostname': hostname, 'fqdn': fqdn})
 
 # vi: ts=4 expandtab
diff --git a/cloudinit/config/cc_ubuntu_advantage.py b/cloudinit/config/cc_ubuntu_advantage.py
index 35ded5db..d61dc655 100644
--- a/cloudinit/config/cc_ubuntu_advantage.py
+++ b/cloudinit/config/cc_ubuntu_advantage.py
@@ -115,7 +115,7 @@ def configure_ua(token=None, enable=None):
         msg = 'Failure attaching Ubuntu Advantage:\n{error}'.format(
             error=str(e))
         util.logexc(LOG, msg)
-        raise RuntimeError(msg)
+        raise RuntimeError(msg) from e
     enable_errors = []
     for service in enable:
         try:
diff --git a/cloudinit/config/schema.py b/cloudinit/config/schema.py
index 2d8c7577..8a966aee 100644
--- a/cloudinit/config/schema.py
+++ b/cloudinit/config/schema.py
@@ -210,7 +210,7 @@ def validate_cloudconfig_file(config_path, schema, annotate=False):
         error = SchemaValidationError(errors)
         if annotate:
             print(annotated_cloudconfig_file({}, content, error.schema_errors))
-        raise error
+        raise error from e
     try:
         validate_cloudconfig_schema(
             cloudconfig, schema, strict=True)
diff --git a/cloudinit/distros/__init__.py b/cloudinit/distros/__init__.py
index effb4276..2537608f 100755
--- a/cloudinit/distros/__init__.py
+++ b/cloudinit/distros/__init__.py
@@ -607,10 +607,11 @@ class Distro(metaclass=abc.ABCMeta):
         lock_tools = (['passwd', '-l', name], ['usermod', '--lock', name])
         try:
             cmd = next(tool for tool in lock_tools if subp.which(tool[0]))
-        except StopIteration:
+        except StopIteration as e:
             raise RuntimeError((
                 "Unable to lock user account '%s'. No tools available. "
-                "  Tried: %s.") % (name, [c[0] for c in lock_tools]))
+                "  Tried: %s.") % (name, [c[0] for c in lock_tools])
+            ) from e
         try:
             subp.subp(cmd)
         except Exception as e:
diff --git a/cloudinit/distros/arch.py b/cloudinit/distros/arch.py
index 038aa9ac..967be168 100644
--- a/cloudinit/distros/arch.py
+++ b/cloudinit/distros/arch.py
@@ -61,9 +61,9 @@ class Distro(distros.Distro):
     def _write_network_config(self, netconfig):
         try:
             return self._supported_write_network_config(netconfig)
-        except RendererNotFoundError:
+        except RendererNotFoundError as e:
             # Fall back to old _write_network
-            raise NotImplementedError
+            raise NotImplementedError from e
 
     def _write_network(self, settings):
         entries = net_util.translate_network(settings)
diff --git a/cloudinit/distros/parsers/resolv_conf.py b/cloudinit/distros/parsers/resolv_conf.py
index 299d54b5..62929d03 100644
--- a/cloudinit/distros/parsers/resolv_conf.py
+++ b/cloudinit/distros/parsers/resolv_conf.py
@@ -150,9 +150,10 @@ class ResolvConf(object):
                 tail = ''
             try:
                 (cfg_opt, cfg_values) = head.split(None, 1)
-            except (IndexError, ValueError):
-                raise IOError("Incorrectly formatted resolv.conf line %s"
-                              % (i + 1))
+            except (IndexError, ValueError) as e:
+                raise IOError(
+                    "Incorrectly formatted resolv.conf line %s" % (i + 1)
+                ) from e
             if cfg_opt not in ['nameserver', 'domain',
                                'search', 'sortlist', 'options']:
                 raise IOError("Unexpected resolv.conf option %s" % (cfg_opt))
diff --git a/cloudinit/gpg.py b/cloudinit/gpg.py
index 72b5ac59..be0ca0ea 100644
--- a/cloudinit/gpg.py
+++ b/cloudinit/gpg.py
@@ -63,10 +63,11 @@ def recv_key(key, keyserver, retries=(1, 1)):
                 "Import failed with exit code %d, will try again in %ss",
                 error.exit_code, naplen)
             time.sleep(naplen)
-        except StopIteration:
+        except StopIteration as e:
             raise ValueError(
                 ("Failed to import key '%s' from keyserver '%s' "
-                 "after %d tries: %s") % (key, keyserver, trynum, error))
+                 "after %d tries: %s") % (key, keyserver, trynum, error)
+            ) from e
 
 
 def delete_key(key):
diff --git a/cloudinit/handlers/jinja_template.py b/cloudinit/handlers/jinja_template.py
index ce3accf6..aadfbf86 100644
--- a/cloudinit/handlers/jinja_template.py
+++ b/cloudinit/handlers/jinja_template.py
@@ -83,7 +83,8 @@ def render_jinja_payload_from_file(
         if e.errno == EACCES:
             raise RuntimeError(
                 'Cannot render jinja template vars. No read permission on'
-                " '%s'. Try sudo" % instance_data_file)
+                " '%s'. Try sudo" % instance_data_file
+            ) from e
 
     rendered_payload = render_jinja_payload(
         payload, payload_fn, instance_data, debug)
diff --git a/cloudinit/net/__init__.py b/cloudinit/net/__init__.py
index 322af77b..e233149a 100644
--- a/cloudinit/net/__init__.py
+++ b/cloudinit/net/__init__.py
@@ -506,7 +506,9 @@ def apply_network_config_names(netcfg, strict_present=True, strict_busy=True):
     try:
         _rename_interfaces(extract_physdevs(netcfg))
     except RuntimeError as e:
-        raise RuntimeError('Failed to apply network config names: %s' % e)
+        raise RuntimeError(
+            'Failed to apply network config names: %s' % e
+        ) from e
 
 
 def interface_has_own_mac(ifname, strict=False):
@@ -965,7 +967,8 @@ class EphemeralIPv4Network(object):
             self.prefix = mask_to_net_prefix(prefix_or_mask)
         except ValueError as e:
             raise ValueError(
-                'Cannot setup network: {0}'.format(e))
+                'Cannot setup network: {0}'.format(e)
+            ) from e
 
         self.connectivity_url = connectivity_url
         self.interface = interface
diff --git a/cloudinit/net/cmdline.py b/cloudinit/net/cmdline.py
index 7ca7262b..cc8dc17b 100755
--- a/cloudinit/net/cmdline.py
+++ b/cloudinit/net/cmdline.py
@@ -112,8 +112,8 @@ def _klibc_to_config_entry(content, mac_addrs=None):
     data = util.load_shell_content(content)
     try:
         name = data['DEVICE'] if 'DEVICE' in data else data['DEVICE6']
-    except KeyError:
-        raise ValueError("no 'DEVICE' or 'DEVICE6' entry in data")
+    except KeyError as e:
+        raise ValueError("no 'DEVICE' or 'DEVICE6' entry in data") from e
 
     # ipconfig on precise does not write PROTO
     # IPv6 config gives us IPV6PROTO, not PROTO.
diff --git a/cloudinit/net/dhcp.py b/cloudinit/net/dhcp.py
index 9230cf7a..4394c68b 100644
--- a/cloudinit/net/dhcp.py
+++ b/cloudinit/net/dhcp.py
@@ -82,8 +82,8 @@ class EphemeralDHCPv4(object):
         try:
             leases = maybe_perform_dhcp_discovery(
                 self.iface, self.dhcp_log_func)
-        except InvalidDHCPLeaseFileError:
-            raise NoDHCPLeaseError()
+        except InvalidDHCPLeaseFileError as e:
+            raise NoDHCPLeaseError() from e
         if not leases:
             raise NoDHCPLeaseError()
         self.lease = leases[-1]
diff --git a/cloudinit/net/network_state.py b/cloudinit/net/network_state.py
index 7bfe8be0..b2f7d31e 100644
--- a/cloudinit/net/network_state.py
+++ b/cloudinit/net/network_state.py
@@ -297,9 +297,10 @@ class NetworkStateInterpreter(metaclass=CommandHandlerMeta):
             command_type = command['type']
             try:
                 handler = self.command_handlers[command_type]
-            except KeyError:
-                raise RuntimeError("No handler found for"
-                                   " command '%s'" % command_type)
+            except KeyError as e:
+                raise RuntimeError(
+                    "No handler found for  command '%s'" % command_type
+                ) from e
             try:
                 handler(self, command)
             except InvalidCommand:
@@ -316,9 +317,10 @@ class NetworkStateInterpreter(metaclass=CommandHandlerMeta):
                 continue
             try:
                 handler = self.command_handlers[command_type]
-            except KeyError:
-                raise RuntimeError("No handler found for"
-                                   " command '%s'" % command_type)
+            except KeyError as e:
+                raise RuntimeError(
+                    "No handler found for command '%s'" % command_type
+                ) from e
             try:
                 handler(self, command)
                 self._v2_common(command)
@@ -914,9 +916,10 @@ def _normalize_route(route):
     if metric:
         try:
             normal_route['metric'] = int(metric)
-        except ValueError:
+        except ValueError as e:
             raise TypeError(
-                'Route config metric {} is not an integer'.format(metric))
+                'Route config metric {} is not an integer'.format(metric)
+            ) from e
     return normal_route
 
 
diff --git a/cloudinit/sources/DataSourceAzure.py b/cloudinit/sources/DataSourceAzure.py
index 86cc7c28..f3c6452b 100755
--- a/cloudinit/sources/DataSourceAzure.py
+++ b/cloudinit/sources/DataSourceAzure.py
@@ -1147,7 +1147,7 @@ def read_azure_ovf(contents):
     except Exception as e:
         error_str = "Invalid ovf-env.xml: %s" % e
         report_diagnostic_event(error_str)
-        raise BrokenAzureDataSource(error_str)
+        raise BrokenAzureDataSource(error_str) from e
 
     results = find_child(dom.documentElement,
                          lambda n: n.localName == "ProvisioningSection")
diff --git a/cloudinit/sources/DataSourceEc2.py b/cloudinit/sources/DataSourceEc2.py
index 355b4e2f..1d09c12a 100644
--- a/cloudinit/sources/DataSourceEc2.py
+++ b/cloudinit/sources/DataSourceEc2.py
@@ -617,9 +617,11 @@ def parse_strict_mode(cfgval):
     if sleep:
         try:
             sleep = int(sleep)
-        except ValueError:
-            raise ValueError("Invalid sleep '%s' in strict_id setting '%s': "
-                             "not an integer" % (sleep, cfgval))
+        except ValueError as e:
+            raise ValueError(
+                "Invalid sleep '%s' in strict_id setting '%s': not an integer"
+                % (sleep, cfgval)
+            ) from e
     else:
         sleep = None
 
diff --git a/cloudinit/sources/DataSourceIBMCloud.py b/cloudinit/sources/DataSourceIBMCloud.py
index d2aa9a58..8d196185 100644
--- a/cloudinit/sources/DataSourceIBMCloud.py
+++ b/cloudinit/sources/DataSourceIBMCloud.py
@@ -303,7 +303,8 @@ def read_md():
     except sources.BrokenMetadata as e:
         raise RuntimeError(
             "Failed reading IBM config disk (platform=%s path=%s): %s" %
-            (platform, path, e))
+            (platform, path, e)
+        ) from e
 
     ret.update(results)
     return ret
diff --git a/cloudinit/sources/DataSourceMAAS.py b/cloudinit/sources/DataSourceMAAS.py
index c80f70c2..9156925f 100644
--- a/cloudinit/sources/DataSourceMAAS.py
+++ b/cloudinit/sources/DataSourceMAAS.py
@@ -226,7 +226,8 @@ def read_maas_seed_url(seed_url, read_file_or_url=None, timeout=None,
         except url_helper.UrlError as e:
             if e.code == 404 and not optional:
                 raise MAASSeedDirMalformed(
-                    "Missing required %s: %s" % (path, e))
+                    "Missing required %s: %s" % (path, e)
+                ) from e
             elif e.code != 404:
                 raise e
 
diff --git a/cloudinit/sources/DataSourceOpenNebula.py b/cloudinit/sources/DataSourceOpenNebula.py
index 12b1f94f..45481938 100644
--- a/cloudinit/sources/DataSourceOpenNebula.py
+++ b/cloudinit/sources/DataSourceOpenNebula.py
@@ -399,18 +399,23 @@ def read_context_disk_dir(source_dir, distro, asuser=None):
         if asuser is not None:
             try:
                 pwd.getpwnam(asuser)
-            except KeyError:
+            except KeyError as e:
                 raise BrokenContextDiskDir(
                     "configured user '{user}' does not exist".format(
-                        user=asuser))
+                        user=asuser)
+                ) from e
         try:
             path = os.path.join(source_dir, 'context.sh')
             content = util.load_file(path)
             context = parse_shell_config(content, asuser=asuser)
         except subp.ProcessExecutionError as e:
-            raise BrokenContextDiskDir("Error processing context.sh: %s" % (e))
+            raise BrokenContextDiskDir(
+                "Error processing context.sh: %s" % (e)
+            ) from e
         except IOError as e:
-            raise NonContextDiskDir("Error reading context.sh: %s" % (e))
+            raise NonContextDiskDir(
+                "Error reading context.sh: %s" % (e)
+            ) from e
     else:
         raise NonContextDiskDir("Missing context.sh")
 
diff --git a/cloudinit/sources/DataSourceOpenStack.py b/cloudinit/sources/DataSourceOpenStack.py
index bf539091..d4b43f44 100644
--- a/cloudinit/sources/DataSourceOpenStack.py
+++ b/cloudinit/sources/DataSourceOpenStack.py
@@ -194,10 +194,10 @@ class DataSourceOpenStack(openstack.SourceMixin, sources.DataSource):
                         'timeout': url_params.timeout_seconds})
         except openstack.NonReadable as e:
             raise sources.InvalidMetaDataException(str(e))
-        except (openstack.BrokenMetadata, IOError):
+        except (openstack.BrokenMetadata, IOError) as e:
             msg = 'Broken metadata address {addr}'.format(
                 addr=self.metadata_address)
-            raise sources.InvalidMetaDataException(msg)
+            raise sources.InvalidMetaDataException(msg) from e
         return result
 
 
diff --git a/cloudinit/sources/DataSourceSmartOS.py b/cloudinit/sources/DataSourceSmartOS.py
index 843b3a2a..f1f903bc 100644
--- a/cloudinit/sources/DataSourceSmartOS.py
+++ b/cloudinit/sources/DataSourceSmartOS.py
@@ -413,7 +413,9 @@ class JoyentMetadataClient(object):
                 response.append(byte)
             except OSError as exc:
                 if exc.errno == errno.EAGAIN:
-                    raise JoyentMetadataTimeoutException(msg % as_ascii())
+                    raise JoyentMetadataTimeoutException(
+                        msg % as_ascii()
+                    ) from exc
                 raise
 
     def _write(self, msg):
diff --git a/cloudinit/sources/helpers/azure.py b/cloudinit/sources/helpers/azure.py
index 6156c75b..b968a96f 100755
--- a/cloudinit/sources/helpers/azure.py
+++ b/cloudinit/sources/helpers/azure.py
@@ -98,8 +98,10 @@ def get_boot_telemetry():
     LOG.debug("Collecting boot telemetry")
     try:
         kernel_start = float(time.time()) - float(util.uptime())
-    except ValueError:
-        raise RuntimeError("Failed to determine kernel start timestamp")
+    except ValueError as e:
+        raise RuntimeError(
+            "Failed to determine kernel start timestamp"
+        ) from e
 
     try:
         out, _ = subp.subp(['/bin/systemctl',
@@ -116,12 +118,13 @@ def get_boot_telemetry():
 
         user_start = kernel_start + (float(tsm) / 1000000)
     except subp.ProcessExecutionError as e:
-        raise RuntimeError("Failed to get UserspaceTimestampMonotonic: %s"
-                           % e)
+        raise RuntimeError(
+            "Failed to get UserspaceTimestampMonotonic: %s" % e
+        ) from e
     except ValueError as e:
-        raise RuntimeError("Failed to parse "
-                           "UserspaceTimestampMonotonic from systemd: %s"
-                           % e)
+        raise RuntimeError(
+            "Failed to parse UserspaceTimestampMonotonic from systemd: %s" % e
+        ) from e
 
     try:
         out, _ = subp.subp(['/bin/systemctl', 'show',
@@ -137,12 +140,14 @@ def get_boot_telemetry():
 
         cloudinit_activation = kernel_start + (float(tsm) / 1000000)
     except subp.ProcessExecutionError as e:
-        raise RuntimeError("Failed to get InactiveExitTimestampMonotonic: %s"
-                           % e)
+        raise RuntimeError(
+            "Failed to get InactiveExitTimestampMonotonic: %s" % e
+        ) from e
     except ValueError as e:
-        raise RuntimeError("Failed to parse "
-                           "InactiveExitTimestampMonotonic from systemd: %s"
-                           % e)
+        raise RuntimeError(
+            "Failed to parse InactiveExitTimestampMonotonic from systemd: %s"
+            % e
+        ) from e
 
     evt = events.ReportingEvent(
         BOOT_EVENT_TYPE, 'boot-telemetry',
@@ -642,9 +647,10 @@ class WALinuxAgentShim:
             try:
                 name = os.path.basename(hook_file).replace('.json', '')
                 dhcp_options[name] = json.loads(util.load_file((hook_file)))
-            except ValueError:
+            except ValueError as e:
                 raise ValueError(
-                    '{_file} is not valid JSON data'.format(_file=hook_file))
+                    '{_file} is not valid JSON data'.format(_file=hook_file)
+                ) from e
         return dhcp_options
 
     @staticmethod
diff --git a/cloudinit/sources/helpers/netlink.py b/cloudinit/sources/helpers/netlink.py
index a74a3588..c2ad587b 100644
--- a/cloudinit/sources/helpers/netlink.py
+++ b/cloudinit/sources/helpers/netlink.py
@@ -74,7 +74,7 @@ def create_bound_netlink_socket():
         netlink_socket.setblocking(0)
     except socket.error as e:
         msg = "Exception during netlink socket create: %s" % e
-        raise NetlinkCreateSocketError(msg)
+        raise NetlinkCreateSocketError(msg) from e
     LOG.debug("Created netlink socket")
     return netlink_socket
 
diff --git a/cloudinit/sources/helpers/openstack.py b/cloudinit/sources/helpers/openstack.py
index 1050efb0..65e020c5 100644
--- a/cloudinit/sources/helpers/openstack.py
+++ b/cloudinit/sources/helpers/openstack.py
@@ -280,8 +280,9 @@ class BaseReader(metaclass=abc.ABCMeta):
                 try:
                     data = translator(data)
                 except Exception as e:
-                    raise BrokenMetadata("Failed to process "
-                                         "path %s: %s" % (path, e))
+                    raise BrokenMetadata(
+                        "Failed to process path %s: %s" % (path, e)
+                    ) from e
             if found:
                 results[name] = data
 
@@ -291,8 +292,9 @@ class BaseReader(metaclass=abc.ABCMeta):
             try:
                 metadata['random_seed'] = base64.b64decode(random_seed)
             except (ValueError, TypeError) as e:
-                raise BrokenMetadata("Badly formatted metadata"
-                                     " random_seed entry: %s" % e)
+                raise BrokenMetadata(
+                    "Badly formatted metadata random_seed entry: %s" % e
+                ) from e
 
         # load any files that were provided
         files = {}
@@ -304,8 +306,9 @@ class BaseReader(metaclass=abc.ABCMeta):
             try:
                 files[path] = self._read_content_path(item)
             except Exception as e:
-                raise BrokenMetadata("Failed to read provided "
-                                     "file %s: %s" % (path, e))
+                raise BrokenMetadata(
+                    "Failed to read provided file %s: %s" % (path, e)
+                ) from e
         results['files'] = files
 
         # The 'network_config' item in metadata is a content pointer
@@ -317,8 +320,9 @@ class BaseReader(metaclass=abc.ABCMeta):
                 content = self._read_content_path(net_item, decode=True)
                 results['network_config'] = content
             except IOError as e:
-                raise BrokenMetadata("Failed to read network"
-                                     " configuration: %s" % (e))
+                raise BrokenMetadata(
+                    "Failed to read network configuration: %s" % (e)
+                ) from e
 
         # To openstack, user can specify meta ('nova boot --meta=key=value')
         # and those will appear under metadata['meta'].
@@ -370,8 +374,9 @@ class ConfigDriveReader(BaseReader):
             try:
                 return util.load_json(self._path_read(path))
             except Exception as e:
-                raise BrokenMetadata("Failed to process "
-                                     "path %s: %s" % (path, e))
+                raise BrokenMetadata(
+                    "Failed to process path %s: %s" % (path, e)
+                ) from e
 
     def read_v1(self):
         """Reads a version 1 formatted location.
@@ -395,16 +400,17 @@ class ConfigDriveReader(BaseReader):
                 path = found[name]
                 try:
                     contents = self._path_read(path)
-                except IOError:
-                    raise BrokenMetadata("Failed to read: %s" % path)
+                except IOError as e:
+                    raise BrokenMetadata("Failed to read: %s" % path) from e
                 try:
                     # Disable not-callable pylint check; pylint isn't able to
                     # determine that every member of FILES_V1 has a callable in
                     # the appropriate position
                     md[key] = translator(contents)  # pylint: disable=E1102
                 except Exception as e:
-                    raise BrokenMetadata("Failed to process "
-                                         "path %s: %s" % (path, e))
+                    raise BrokenMetadata(
+                        "Failed to process path %s: %s" % (path, e)
+                    ) from e
             else:
                 md[key] = copy.deepcopy(default)
 
diff --git a/cloudinit/subp.py b/cloudinit/subp.py
index 804ef3ca..3e4efa42 100644
--- a/cloudinit/subp.py
+++ b/cloudinit/subp.py
@@ -262,7 +262,8 @@ def subp(args, data=None, rcs=None, env=None, capture=True,
         raise ProcessExecutionError(
             cmd=args, reason=e, errno=e.errno,
             stdout="-" if decode else b"-",
-            stderr="-" if decode else b"-")
+            stderr="-" if decode else b"-"
+        ) from e
     finally:
         if devnull_fp:
             devnull_fp.close()
diff --git a/cloudinit/url_helper.py b/cloudinit/url_helper.py
index f3c0cf9c..caa88435 100644
--- a/cloudinit/url_helper.py
+++ b/cloudinit/url_helper.py
@@ -95,7 +95,7 @@ def read_file_or_url(url, **kwargs):
             code = e.errno
             if e.errno == ENOENT:
                 code = NOT_FOUND
-            raise UrlError(cause=e, code=code, headers=None, url=url)
+            raise UrlError(cause=e, code=code, headers=None, url=url) from e
         return FileResponse(file_path, contents=contents)
     else:
         return readurl(url, **kwargs)
@@ -575,8 +575,8 @@ def oauth_headers(url, consumer_key, token_key, token_secret, consumer_secret,
                   timestamp=None):
     try:
         import oauthlib.oauth1 as oauth1
-    except ImportError:
-        raise NotImplementedError('oauth support is not available')
+    except ImportError as e:
+        raise NotImplementedError('oauth support is not available') from e
 
     if timestamp:
         timestamp = str(timestamp)
diff --git a/cloudinit/util.py b/cloudinit/util.py
index dd263803..cf9e349f 100644
--- a/cloudinit/util.py
+++ b/cloudinit/util.py
@@ -359,7 +359,7 @@ def decomp_gzip(data, quiet=True, decode=True):
         if quiet:
             return data
         else:
-            raise DecompressionError(str(e))
+            raise DecompressionError(str(e)) from e
 
 
 def extract_usergroup(ug_pair):
@@ -1363,7 +1363,7 @@ def chownbyname(fname, user=None, group=None):
         if group:
             gid = grp.getgrnam(group).gr_gid
     except KeyError as e:
-        raise OSError("Unknown user or group: %s" % (e))
+        raise OSError("Unknown user or group: %s" % (e)) from e
     chownbyid(fname, uid, gid)
 
 
@@ -2387,8 +2387,8 @@ def human2bytes(size):
 
     try:
         num = float(num)
-    except ValueError:
-        raise ValueError("'%s' is not valid input." % size_in)
+    except ValueError as e:
+        raise ValueError("'%s' is not valid input." % size_in) from e
 
     if num < 0:
         raise ValueError("'%s': cannot be negative" % size_in)