1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
|
:title: Configuration
Configuration
=============
All Zuul processes read the ``/etc/zuul/zuul.conf`` file (an alternate
location may be supplied on the command line) which uses an INI file
syntax. Each component may have its own configuration file, though
you may find it simpler to use the same file for all components.
Zuul will interpolate environment variables starting with the
``ZUUL_`` prefix given in the config file escaped as python string
expansion. ``foo=%(ZUUL_HOME)s`` will set the value of ``foo`` to the
same value as the environment variable named ``ZUUL_HOME``.
An example ``zuul.conf``:
.. code-block:: ini
[zookeeper]
hosts=zk1.example.com,zk2.example.com,zk3.example.com
[database]
dburi=<URI>
[keystore]
password=MY_SECRET_PASSWORD
[web]
status_url=https://zuul.example.com/status
[scheduler]
log_config=/etc/zuul/scheduler-logging.yaml
Common Options
--------------
The following sections of ``zuul.conf`` are used by all Zuul components:
Statsd
~~~~~~
.. attr:: statsd
Information about the optional statsd server. If the ``statsd``
python module is installed and this section is configured,
statistics will be reported to statsd. See :ref:`statsd` for more
information.
.. attr:: server
Hostname or IP address of the statsd server.
.. attr:: port
:default: 8125
The UDP port on which the statsd server is listening.
.. attr:: prefix
If present, this will be prefixed to all of the keys before
transmitting to the statsd server.
ZooKeeper
~~~~~~~~~
.. attr:: zookeeper
Client connection information for ZooKeeper. TLS is required.
.. attr:: hosts
:required:
A list of zookeeper hosts for Zuul to use when communicating
with Nodepool.
.. attr:: tls_cert
:required:
The path to the PEM encoded certificate file.
.. attr:: tls_key
:required:
The path to the PEM encoded key file.
.. attr:: tls_ca
:required:
The path to the PEM encoded CA certificate file.
.. attr:: session_timeout
:default: 10.0
The ZooKeeper session timeout, in seconds.
.. _database:
Database
~~~~~~~~
.. attr:: database
.. attr:: dburi
:required:
Database connection information in the form of a URI understood
by SQLAlchemy. See `The SQLAlchemy manual
<https://docs.sqlalchemy.org/en/latest/core/engines.html#database-urls>`_
for more information.
The driver will automatically set up the database creating and managing
the necessary tables. Therefore the provided user should have sufficient
permissions to manage the database. For example:
.. code-block:: sql
GRANT ALL ON my_database TO 'my_user'@'%';
.. attr:: pool_recycle
:default: 1
Tune the pool_recycle value. See `The SQLAlchemy manual on pooling
<http://docs.sqlalchemy.org/en/latest/core/pooling.html#setting-pool-recycle>`_
for more information.
.. attr:: table_prefix
:default: ''
The string to prefix the table names. This makes it possible to run
several zuul deployments against the same database. This can be useful
if you rely on external databases which are not under your control.
The default is to have no prefix.
.. _scheduler:
Scheduler
---------
The scheduler is the primary component of Zuul. The scheduler is a
scalable component; one or more schedulers must be running at all
times for Zuul to be operational. It receives events from any
connections to remote systems which have been configured, enqueues
items into pipelines, distributes jobs to executors, and reports
results.
The scheduler must be able to connect to the ZooKeeper cluster shared
by Zuul and Nodepool in order to request nodes. It does not need to
connect directly to the nodes themselves, however -- that function is
handled by the Executors.
It must also be able to connect to any services for which connections
are configured (Gerrit, GitHub, etc).
The following sections of ``zuul.conf`` are used by the scheduler:
.. attr:: web
.. attr:: root
:required:
The root URL of the web service (e.g.,
``https://zuul.example.com/``).
See :attr:`tenant.web-root` for additional options for
whitelabeled tenant configuration.
.. attr:: status_url
URL that will be posted in Zuul comments made to changes when
starting jobs for a change.
.. TODO: is this effectively required?
.. attr:: keystore
.. attr:: password
:required:
Encryption password for private data stored in Zookeeper.
.. attr:: scheduler
.. attr:: command_socket
:default: /var/lib/zuul/scheduler.socket
Path to command socket file for the scheduler process.
.. attr:: tenant_config
Path to :ref:`tenant-config` file. This attribute
is exclusive with :attr:`scheduler.tenant_config_script`.
.. attr:: tenant_config_script
Path to a script to execute and load the tenant
config from. This attribute is exclusive with
:attr:`scheduler.tenant_config`.
.. attr:: default_ansible_version
Default ansible version to use for jobs that doesn't specify a version.
See :attr:`job.ansible-version` for details.
.. attr:: log_config
Path to log config file.
.. attr:: pidfile
:default: /var/run/zuul/scheduler.pid
Path to PID lock file.
.. attr:: relative_priority
:default: False
A boolean which indicates whether the scheduler should supply
relative priority information for node requests.
In all cases, each pipeline may specify a precedence value which
is used by Nodepool to satisfy requests from higher-precedence
pipelines first. If ``relative_priority`` is set to ``True``,
then Zuul will additionally group items in the same pipeline by
pipeline queue and weight each request by its position in that
project's group. A request for the first change in a given
queue will have the highest relative priority, and the second
change a lower relative priority. The first change of each
queue in a pipeline has the same relative priority, regardless
of the order of submission or how many other changes are in the
pipeline. This can be used to make node allocations complete
faster for projects with fewer changes in a system dominated by
projects with more changes.
After the first 10 changes, the relative priority becomes more
coarse (batching groups of 10 changes at the same priority).
Likewise, after 100 changes they are batchen in groups of 100.
This is to avoid causing additional load with unecessary
priority changes if queues are long.
If this value is ``False`` (the default), then node requests are
sorted by pipeline precedence followed by the order in which
they were submitted. If this is ``True``, they are sorted by
pipeline precedence, followed by relative priority, and finally
the order in which they were submitted.
.. attr:: default_hold_expiration
:default: max_hold_expiration
The default value for held node expiration if not supplied. This
will default to the value of ``max_hold_expiration`` if not changed,
or if it is set to a higher value than the max.
.. attr:: max_hold_expiration
:default: 0
Maximum number of seconds any nodes held for an autohold request
will remain available. A value of 0 disables this, and the nodes
will remain held until the autohold request is manually deleted.
If a value higher than ``max_hold_expiration`` is supplied during
hold request creation, it will be lowered to this value.
.. attr:: prometheus_port
Set a TCP port to start the prometheus metrics client.
.. attr:: prometheus_addr
:default: 0.0.0.0
The IPv4 addr to listen for prometheus metrics poll.
To use IPv6, python>3.8 is required `issue24209 <https://bugs.python.org/issue24209>`_.
Merger
------
Mergers are an optional Zuul service; they are not required for Zuul
to operate, but some high volume sites may benefit from running them.
Zuul performs quite a lot of git operations in the course of its work.
Each change that is to be tested must be speculatively merged with the
current state of its target branch to ensure that it can merge, and to
ensure that the tests that Zuul perform accurately represent the
outcome of merging the change. Because Zuul's configuration is stored
in the git repos it interacts with, and is dynamically evaluated, Zuul
often needs to perform a speculative merge in order to determine
whether it needs to perform any further actions.
All of these git operations add up, and while Zuul executors can also
perform them, large numbers may impact their ability to run jobs.
Therefore, administrators may wish to run standalone mergers in order
to reduce the load on executors.
Mergers need to be able to connect to the ZooKeeper cluster as well as
any services for which connections are configured (Gerrit, GitHub,
etc).
The following section of ``zuul.conf`` is used by the merger:
.. attr:: merger
.. attr:: command_socket
:default: /var/lib/zuul/merger.socket
Path to command socket file for the merger process.
.. attr:: git_dir
:default: /var/lib/zuul/merger-git
Directory in which Zuul should clone git repositories.
.. attr:: git_http_low_speed_limit
:default: 1000
If the HTTP transfer speed is less then git_http_low_speed_limit for
longer then git_http_low_speed_time, the transfer is aborted.
Value in bytes, setting to 0 will disable.
.. attr:: git_http_low_speed_time
:default: 30
If the HTTP transfer speed is less then git_http_low_speed_limit for
longer then git_http_low_speed_time, the transfer is aborted.
Value in seconds, setting to 0 will disable.
.. attr:: git_timeout
:default: 300
Timeout for git clone and fetch operations. This can be useful when
dealing with large repos. Note that large timeouts can increase startup
and reconfiguration times if repos are not cached so be cautious when
increasing this value.
Value in seconds.
.. attr:: git_user_email
Value to pass to `git config user.email
<https://git-scm.com/book/en/v2/Getting-Started-First-Time-Git-Setup>`_.
.. attr:: git_user_name
Value to pass to `git config user.name
<https://git-scm.com/book/en/v2/Getting-Started-First-Time-Git-Setup>`_.
.. attr:: log_config
Path to log config file for the merger process.
.. attr:: pidfile
:default: /var/run/zuul/merger.pid
Path to PID lock file for the merger process.
.. attr:: prometheus_port
Set a TCP port to start the prometheus metrics client.
.. attr:: prometheus_addr
:default: 0.0.0.0
The IPv4 addr to listen for prometheus metrics poll.
To use IPv6, python>3.8 is required `issue24209 <https://bugs.python.org/issue24209>`_.
.. _executor:
Executor
--------
Executors are responsible for running jobs. At the start of each job,
an executor prepares an environment in which to run Ansible which
contains all of the git repositories specified by the job with all
dependent changes merged into their appropriate branches. The branch
corresponding to the proposed change will be checked out (in all
projects, if it exists). Any roles specified by the job will also be
present (also with dependent changes merged, if appropriate) and added
to the Ansible role path. The executor also prepares an Ansible
inventory file with all of the nodes requested by the job.
The executor also contains a merger. This is used by the executor to
prepare the git repositories used by jobs, but is also available to
perform any tasks normally performed by standalone mergers. Because
the executor performs both roles, small Zuul installations may not
need to run standalone mergers.
Executors need to be able to connect to the ZooKeeper cluster, any
services for which connections are configured (Gerrit, GitHub, etc),
as well as directly to the hosts which Nodepool provides.
Trusted and Untrusted Playbooks
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The executor runs playbooks in one of two execution contexts depending
on whether the project containing the playbook is a
:term:`config-project` or an :term:`untrusted-project`. If the
playbook is in a config project, the executor runs the playbook in the
*trusted* execution context, otherwise, it is run in the *untrusted*
execution context.
Both execution contexts use `bubblewrap`_ to create a namespace to
ensure that playbook executions are isolated and are unable to access
files outside of a restricted environment. The administrator may
configure additional local directories on the executor to be made
available to the restricted environment.
.. _bubblewrap: https://github.com/projectatomic/bubblewrap
.. _executor_security:
Security Considerations
~~~~~~~~~~~~~~~~~~~~~~~
Bubblewrap restricts access to files outside of the build environment
in both execution contexts. Operators may allow either read-only or
read-write access to additional paths in either the `trusted` context
or both contexts with additional options described below. Be careful
when adding additional paths, and consider that any `trusted` or
`untrusted` (as appropriate) playbook will have access to these paths.
If executors are configured to use WinRM certificates, these must be
made available to the bubblewrap environment in order for Ansible to
use them. This invariably makes them accessible to any playbook in
that execution context. Operators may want to consider only supplying
WinRM credentials to trusted playbooks and installing per-build
certificates in a pre-playbook; or using Ansible's experimental SSH
support instead of WinRM.
Local code execution is permitted on the executor, so if a
vulnerability in bubblewrap or the kernel allows for an escape from
the restricted environment, users may be able to escalate their
privileges and obtain access to any data or secrets available to the
executor.
Playbooks which run on the executor will have the same network access
as the executor itself. This should be kept in mind when considering
IP-based network access control within an organization. Zuul's
internal communication is via ZooKeeper which is authenticated and
secured by TLS certificates, so as long as these certificates are not
made available to jobs, users should not be able to access or disrupt
Zuul's internal communications. However, statsd is an unauthenticated
protocol, so a malicious user could emit false statsd information.
If the Zuul executor is running in a cloud environment with a network
metadata service, users may be able to access that service. If it
supplies credentials, they may be able to obtain those credentials and
access cloud resources. Operators should ensure that in these
environments, the executors are configured with appropriately
restricted IAM profiles.
Configuration
~~~~~~~~~~~~~
The following sections of ``zuul.conf`` are used by the executor:
.. attr:: executor
.. attr:: command_socket
:default: /var/lib/zuul/executor.socket
Path to command socket file for the executor process.
.. attr:: finger_port
:default: 7900
Port to use for finger log streamer.
.. attr:: state_dir
:default: /var/lib/zuul
Path to directory in which Zuul should save its state.
.. attr:: git_dir
:default: /var/lib/zuul/executor-git
Directory that Zuul should clone local git repositories to. The
executor keeps a local copy of every git repository it works
with to speed operations and perform speculative merging.
This should be on the same filesystem as
:attr:`executor.job_dir` so that when git repos are cloned into
the job workspaces, they can be hard-linked to the local git
cache.
.. attr:: job_dir
:default: /var/lib/zuul/builds
Directory that Zuul should use to hold temporary job directories.
When each job is run, a new entry will be created under this
directory to hold the configuration and scratch workspace for
that job. It will be deleted at the end of the job (unless the
`--keep-jobdir` command line option is specified).
This should be on the same filesystem as :attr:`executor.git_dir`
so that when git repos are cloned into the job workspaces, they
can be hard-linked to the local git cache.
.. attr:: log_config
Path to log config file for the executor process.
.. attr:: pidfile
:default: /var/run/zuul/executor.pid
Path to PID lock file for the executor process.
.. attr:: private_key_file
:default: ~/.ssh/id_rsa
SSH private key file to be used when logging into worker nodes.
.. note:: If you use an RSA key, ensure it is encoded in the PEM
format (use the ``-t rsa -m PEM`` arguments to
`ssh-keygen`).
.. attr:: default_username
:default: zuul
Username to use when logging into worker nodes, if none is
supplied by Nodepool.
.. attr:: winrm_cert_key_file
:default: ~/.winrm/winrm_client_cert.key
The private key file of the client certificate to use for winrm
connections to Windows nodes.
.. attr:: winrm_cert_pem_file
:default: ~/.winrm/winrm_client_cert.pem
The certificate file of the client certificate to use for winrm
connections to Windows nodes.
.. note:: Currently certificate verification is disabled when
connecting to Windows nodes via winrm.
.. attr:: winrm_operation_timeout_sec
:default: None. The Ansible default of 20 is used in this case.
The timeout for WinRM operations.
.. attr:: winrm_read_timeout_sec
:default: None. The Ansible default of 30 is used in this case.
The timeout for WinRM read. Increase this if there are intermittent
network issues and read timeout errors keep occurring.
.. _admin_sitewide_variables:
.. attr:: variables
Path to an Ansible variables file to supply site-wide variables.
This should be a YAML-formatted file consisting of a single
dictionary. The contents will be made available to all jobs as
Ansible variables. These variables take precedence over all
other forms (job variables and secrets). Care should be taken
when naming these variables to avoid potential collisions with
those used by jobs. Prefixing variable names with a
site-specific identifier is recommended. The default is not to
add any site-wide variables. See the :ref:`User's Guide
<user_jobs_sitewide_variables>` for more information.
.. attr:: manage_ansible
:default: True
Specifies wether the zuul-executor should install the supported ansible
versions during startup or not. If this is ``True`` the zuul-executor
will install the ansible versions into :attr:`executor.ansible_root`.
It is recommended to set this to ``False`` and manually install Ansible
after the Zuul installation by running ``zuul-manage-ansible``. This has
the advantage that possible errors during Ansible installation can be
spotted earlier. Further especially containerized deployments of Zuul
will have the advantage of predictable versions.
.. attr:: ansible_root
:default: <state_dir>/ansible-bin
Specifies where the zuul-executor should look for its supported ansible
installations. By default it looks in the following directories and uses
the first which it can find.
* ``<zuul_install_dir>/lib/zuul/ansible``
* ``<ansible_root>``
The ``ansible_root`` setting allows you to override the second location
which is also used for installation if ``manage_ansible`` is ``True``.
.. attr:: ansible_setup_timeout
:default: 60
Timeout of the ansible setup playbook in seconds that runs before
the first playbook of the job.
.. attr:: disk_limit_per_job
:default: 250
This integer is the maximum number of megabytes that any one job
is allowed to consume on disk while it is running. If a job's
scratch space has more than this much space consumed, it will be
aborted. Set to -1 to disable the limit.
.. attr:: trusted_ro_paths
List of paths, separated by ``:`` to read-only bind mount into
trusted bubblewrap contexts.
.. attr:: trusted_rw_paths
List of paths, separated by ``:`` to read-write bind mount into
trusted bubblewrap contexts.
.. attr:: untrusted_ro_paths
List of paths, separated by ``:`` to read-only bind mount into
untrusted bubblewrap contexts.
.. attr:: untrusted_rw_paths
List of paths, separated by ``:`` to read-write bind mount into
untrusted bubblewrap contexts.
.. attr:: load_multiplier
:default: 2.5
When an executor host gets too busy, the system may suffer
timeouts and other ill effects. The executor will stop accepting
more than 1 job at a time until load has lowered below a safe
level. This level is determined by multiplying the number of
CPU's by `load_multiplier`.
So for example, if the system has 2 CPUs, and load_multiplier
is 2.5, the safe load for the system is 5.00. Any time the
system load average is over 5.00, the executor will quit
accepting multiple jobs at one time.
The executor will observe system load and determine whether
to accept more jobs every 30 seconds.
.. attr:: max_starting_builds
:default: None
An executor is accepting up to as many starting builds as defined by the
:attr:`executor.load_multiplier` on systems with more than four CPU cores,
and up to twice as many on systems with four or less CPU cores. For
example, on a system with two CPUs: 2 * 2.5 * 2 - up to ten starting
builds may run on such executor; on systems with eight CPUs: 2.5 * 8 - up
to twenty starting builds may run on such executor.
On systems with high CPU/vCPU count an executor may accept too many
starting builds. This can be overwritten using this option providing a
fixed number of maximum starting builds on an executor.
.. attr:: min_avail_hdd
:default: 5.0
This is the minimum percentage of HDD storage available for the
:attr:`executor.state_dir` directory. The executor will stop accepting
more than 1 job at a time until more HDD storage is available. The
available HDD percentage is calculated from the total available
disk space divided by the total real storage capacity multiplied by
100.
.. attr:: min_avail_mem
:default: 5.0
This is the minimum percentage of system RAM available. The
executor will stop accepting more than 1 job at a time until
more memory is available. The available memory percentage is
calculated from the total available memory divided by the
total real memory multiplied by 100. Buffers and cache are
considered available in the calculation.
.. attr:: hostname
:default: hostname of the server
The executor needs to know its hostname under which it is reachable by
zuul-web. Otherwise live console log streaming doesn't work. In most cases
This is automatically detected correctly. But when running in environments
where it cannot determine its hostname correctly this can be overridden
here.
.. attr:: paused_on_start
:default: false
Whether the executor should start in a paused mode. Such executor will not
accept tasks until it is unpaused.
.. attr:: zone
:default: None
Name of the nodepool executor-zone to exclusively execute all jobs that
have nodes with the specified executor-zone attribute. As an example,
it is possible for nodepool nodes to exist in a cloud without public
accessable IP address. By adding an executor to a zone nodepool nodes
could be configured to use private ip addresses.
To enable this in nodepool, you'll use the node-attributes setting in a
provider pool. For example:
.. code-block:: yaml
pools:
- name: main
node-attributes:
executor-zone: vpn
.. attr:: allow_unzoned
:default: False
If :attr:`executor.zone` is set it by default only processes jobs with
nodes of that specific zone even if the nodes have no zone at all.
Enabling ``allow_unzoned`` lets the executor also take jobs with nodes
without zone.
.. attr:: merge_jobs
:default: True
To disable global merge job, set it to false. This is useful for zoned
executors that are running on slow network where you don't want them to
perform merge operations for any events. The executor will still perform
the merge operations required for the build they are executing.
.. attr:: sigterm_method
:default: graceful
Determines how the executor responds to a ``SIGTERM`` signal.
.. value:: graceful
Stop accepting new jobs and wait for all running jobs to
complete before exiting.
.. value:: stop
Abort all running jobs and exit as soon as possible.
.. attr:: prometheus_port
Set a TCP port to start the prometheus metrics client.
.. attr:: prometheus_addr
:default: 0.0.0.0
The IPv4 addr to listen for prometheus metrics poll.
To use IPv6, python>3.8 is required `issue24209 <https://bugs.python.org/issue24209>`_.
.. attr:: keystore
.. attr:: password
:required:
Encryption password for private data stored in Zookeeper.
.. attr:: merger
.. attr:: git_user_email
Value to pass to `git config user.email
<https://git-scm.com/book/en/v2/Getting-Started-First-Time-Git-Setup>`_.
.. attr:: git_user_name
Value to pass to `git config user.name
<https://git-scm.com/book/en/v2/Getting-Started-First-Time-Git-Setup>`_.
.. attr:: prometheus_port
Set a TCP port to start the prometheus metrics client.
.. attr:: prometheus_addr
:default: 0.0.0.0
The IPv4 addr to listen for prometheus metrics poll.
To use IPv6, python>3.8 is required `issue24209 <https://bugs.python.org/issue24209>`_.
.. attr:: ansible_callback "<name>"
To whitelist ansible callback ``<name>``. Any attributes found is this section
will be added to the ``callback_<name>`` section in ansible.cfg.
An example of what configuring the builtin mail callback would look like.
The configuration in zuul.conf.
.. code-block:: ini
[ansible_callback "mail"]
to = user@example.org
sender = zuul@example.org
Would generate the following in ansible.cfg:
.. code-block:: ini
[defaults]
callback_whitelist = mail
[callback_mail]
to = user@example.org
sender = zuul@example.org
.. _web-server:
Web Server
----------
.. TODO: Turn REST API into a link to swagger docs when we grow them
The Zuul web server serves as the single process handling all HTTP
interactions with Zuul. This includes the websocket interface for live
log streaming, the REST API and the html/javascript dashboard. All three are
served as a holistic web application. For information on additional supported
deployment schemes, see :ref:`web-deployment-options`.
Web servers need to be able to connect to the ZooKeeper cluster and
the SQL database. If a GitHub, Gitlab, or Pagure connection is
configured, they need to be reachable so they may receive
notifications.
In addition to the common configuration sections, the following
sections of ``zuul.conf`` are used by the web server:
.. attr:: web
.. attr:: command_socket
:default: /var/lib/zuul/web.socket
Path to command socket file for the web process.
.. attr:: listen_address
:default: 127.0.0.1
IP address or domain name on which to listen.
.. attr:: log_config
Path to log config file for the web server process.
.. attr:: pidfile
:default: /var/run/zuul/web.pid
Path to PID lock file for the web server process.
.. attr:: port
:default: 9000
Port to use for web server process.
.. attr:: websocket_url
Base URL on which the websocket service is exposed, if different
than the base URL of the web app.
.. attr:: stats_url
Base URL from which statistics emitted via statsd can be queried.
.. attr:: stats_type
:default: graphite
Type of server hosting the statistics information. Currently only
'graphite' is supported by the dashboard.
.. attr:: static_path
:default: zuul/web/static
Path containing the static web assets.
.. attr:: static_cache_expiry
:default: 3600
The Cache-Control max-age response header value for static files served
by the zuul-web. Set to 0 during development to disable Cache-Control.
.. attr:: zone
The zone in which zuul-web is deployed. This is only needed if
there are executors with different zones in the environment and
not all executors are directly addressable from zuul-web. The
parameter specifies the zone where the executors are directly
adressable. Live log streaming will go directly to the executors
of the same zone and be routed to a finger gateway of the target
zone if the zones are different.
In a mixed system (with zoned and unzoned executors) there may
also be zoned and unzoned zuul-web services. Omit the zone
parameter for any unzoned zuul-web servers.
If this is used the finger gateways should be configured accordingly.
.. attr:: keystore
.. attr:: password
:required:
Encryption password for private data stored in Zookeeper.
Authentication
~~~~~~~~~~~~~~
A user can be granted access to protected REST API endpoints by providing a
valid JWT (JSON Web Token) as a bearer token when querying the API endpoints.
JWTs are signed and therefore Zuul must be configured so that signatures can be
verified. More information about the JWT standard can be found on the `IETF's
RFC page <https://tools.ietf.org/html/rfc7519>`_.
This optional section of ``zuul.conf``, if present, will activate the
protected endpoints and configure JWT validation:
.. attr:: auth <authenticator name>
.. attr:: driver
The signing algorithm to use. Accepted values are ``HS256``, ``RS256``,
``RS256withJWKS`` or ``OpenIDConnect``. See below for driver-specific
configuration options.
.. attr:: allow_authz_override
:default: false
Allow a JWT to override predefined access rules. See the section on
:ref:`JWT contents <jwt-format>` for more details on how to grant access
to tenants with a JWT.
.. attr:: realm
The authentication realm.
.. attr:: default
:default: false
If set to ``true``, use this realm as the default authentication realm
when handling HTTP authentication errors.
.. attr:: client_id
The expected value of the "aud" claim in the JWT. This is required for
validation.
.. attr:: issuer_id
The expected value of the "iss" claim in the JWT. This is required for
validation.
.. attr:: uid_claim
:default: sub
The JWT claim that Zuul will use as a unique identifier for the bearer of
a token. This is "sub" by default, as it is usually the purpose of this
claim in a JWT. This identifier is used in audit logs.
.. attr:: max_validity_time
Optional value to ensure a JWT cannot be valid for more than this amount
of time in seconds. This is useful if the Zuul operator has no control
over the service issueing JWTs, and the tokens are too long-lived.
.. attr:: skew
:default: 0
Optional integer value to compensate for skew between Zuul's and the
JWT emitter's respective clocks. Use a negative value if Zuul's clock
is running behind.
This section can be repeated as needed with different authenticators, allowing
access to privileged API actions from several JWT issuers.
Driver-specific attributes
..........................
HS256
,,,,,
This is a symmetrical encryption algorithm that only requires a shared secret
between the JWT issuer and the JWT consumer (ie Zuul). This driver should be
used in test deployments, or in deployments where JWTs may be issued manually
to users.
.. note:: At least one HS256 authenticator should be configured in order to use admin commands with the Zuul command line interface.
.. attr:: secret
:noindex:
The shared secret used to sign JWTs and validate signatures.
RS256
,,,,,
This is an asymmetrical encryption algorithm that requires an RSA key pair. Only
the public key is needed by Zuul for signature validation.
.. attr:: public_key
The path to the public key of the RSA key pair. It must be readable by Zuul.
.. attr:: private_key
Optional. The path to the private key of the RSA key pair. It must be
readable by Zuul.
RS256withJWKS
,,,,,,,,,,,,,
.. warning::
This driver is deprecated, use ``OpenIDConnect`` instead.
Some Identity Providers use key sets (also known as **JWKS**), therefore the key to
use when verifying the Authentication Token's signatures cannot be known in
advance; the key's id is stored in the JWT's header and the key must then be
found in the remote key set.
The key set is usually available at a specific URL that can be found in the
"well-known" configuration of an OpenID Connect Identity Provider.
.. attr:: keys_url
The URL where the Identity Provider's key set can be found. For example, for
Google's OAuth service: https://www.googleapis.com/oauth2/v3/certs
OpenIDConnect
,,,,,,,,,,,,,
Use a third-party Identity Provider implementing the OpenID Connect protocol.
The issuer ID should be an URI, from which the "well-known" configuration URI
of the Identity Provider can be inferred. This is intended to be used for
authentication on Zuul's web user interface.
.. attr:: scope
:default: openid profile
The scope(s) to use when requesting access to a user's details. This attribute
can be multivalued (values must be separated by a space). Most OpenID Connect
Identity Providers support the default scopes "openid profile". A full list
of supported scopes can be found in the well-known configuration of the
Identity Provider under the key "scopes_supported".
.. attr:: keys_url
Optional. The URL where the Identity Provider's key set can be found.
For example, for Google's OAuth service: https://www.googleapis.com/oauth2/v3/certs
The well-known configuration of the Identity Provider should provide this URL
under the key "jwks_uri", therefore this attribute is usually not necessary.
Some providers may not conform to the JWT specification and further
configuration may be necessary. In these cases, the following
additional values may be used:
.. attr:: authority
:default: issuer_id
If the authority in the token response is not the same as the
issuer_id in the request, it may be explicitly set here.
.. attr:: audience
:default: client_id
If the audience in the token response is not the same as the
issuer_id in the request, it may be explicitly set here.
.. attr:: load_user_info
:default: true
If the web UI should skip accessing the "UserInfo" endpoint and
instead rely only on the information returned in the token, set
this to ``false``.
Client
------
Zuul's command line client may be configured to make calls to Zuul's web
server. The client will then look for a ``zuul.conf`` file with a ``webclient``
section to set up the connection over HTTP.
.. note:: At least one authenticator must be configured in Zuul for admin commands to be enabled in the client.
.. attr:: webclient
.. attr:: url
The root URL of Zuul's web server.
.. attr:: verify_ssl
:default: true
Enforce SSL verification when sending requests over to Zuul's web server.
This should only be disabled when working with test servers.
Finger Gateway
--------------
The Zuul finger gateway listens on the standard finger port (79) for
finger requests specifying a build UUID for which it should stream log
results. The gateway will determine which executor is currently running that
build and query that executor for the log stream.
This is intended to be used with the standard finger command line client.
For example::
finger UUID@zuul.example.com
The above would stream the logs for the build identified by `UUID`.
Finger gateway servers need to be able to connect to the ZooKeeper
cluster, as well as the console streaming port on the executors
(usually 7900).
Finger gateways are optional. They may be run for either or both of
the following purposes:
* Allowing end-users to connect to the finger port to stream logs.
* Providing an accessible log streaming port for remote zoned
executors which are otherwise inacessible.
In this case, log streaming requests from finger gateways or
zuul-web will route to the executors via finger gateways in the same
zone.
In addition to the common configuration sections, the following
sections of ``zuul.conf`` are used by the finger gateway:
.. attr:: fingergw
.. attr:: command_socket
:default: /var/lib/zuul/fingergw.socket
Path to command socket file for the executor process.
.. attr:: listen_address
:default: all addresses
IP address or domain name on which to listen.
.. attr:: log_config
Path to log config file for the finger gateway process.
.. attr:: pidfile
:default: /var/run/zuul/fingergw.pid
Path to PID lock file for the finger gateway process.
.. attr:: port
:default: 79
Port to use for the finger gateway. Note that since command line
finger clients cannot usually specify the port, leaving this set to
the default value is highly recommended.
.. attr:: user
User ID for the zuul-fingergw process. In normal operation as a
daemon, the finger gateway should be started as the ``root``
user, but if this option is set, it will drop privileges to this
user during startup. It is recommended to set this option to an
unprivileged user.
.. attr:: hostname
:default: hostname of the server
When running finger gateways in a multi-zone configuration, the
gateway needs to know its hostname under which it is reachable
by zuul-web. Otherwise live console log streaming doesn't
work. In most cases This is automatically detected
correctly. But when running in environments where it cannot
determine its hostname correctly this can be overridden here.
.. attr:: zone
The zone where the finger gateway is located. This is only needed for
live log streaming if the zuul deployment is spread over multiple
zones without the ability to directly connect to all executors from
zuul-web. See :attr:`executor.zone` for further information.
In a mixed system (with zoned and unzoned executors) there may
also be zoned and unzoned finger gateway services. Omit the zone
parameter for any unzoned finger gateway servers.
If the Zuul installation spans an untrusted network (for example, if
there are remote executor zones), it may be necessary to use TLS
between the components that handle log streaming (zuul-executor,
zuul-fingergw, and zuul-web). If so, set the following options.
Note that this section is also read by zuul-web in order to load a
client certificate to use when connecting to a finger gateway which
requires TLS, and it is also read by zuul-executor to load a server
certificate for its console streaming port.
If any of these are present, all three certificate options must be
provided.
.. attr:: tls_cert
The path to the PEM encoded certificate file.
.. attr:: tls_key
The path to the PEM encoded key file.
.. attr:: tls_ca
The path to the PEM encoded CA certificate file.
.. attr:: tls_verify_hostnames
:default: true
In the case of a private CA it may be both safe and convenient
to disable hostname checks. However, if the certificates are
issued by a public CA, hostname verification should be enabled.
.. attr:: tls_client_only
:default: false
In order to provide a finger gateway which can reach remote
finger gateways and executors which use TLS, but does not itself
serve end-users via TLS (i.e., it runs within a protected
network and users access it directly via the finger port), set
this to ``true`` and the finger gateway will not listen on TLS,
but will still use the supplied certificate to make remote TLS
connections.
.. _connections:
Connections
===========
Most of Zuul's configuration is contained in the git repositories upon
which Zuul operates, however, some configuration outside of git
repositories is still required to bootstrap the system. This includes
information on connections between Zuul and other systems, as well as
identifying the projects Zuul uses.
In order to interact with external systems, Zuul must have a
*connection* to that system configured. Zuul includes a number of
:ref:`drivers <drivers>`, each of which implements the functionality
necessary to connect to a system. Each connection in Zuul is
associated with a driver.
To configure a connection in Zuul, select a unique name for the
connection and add a section to ``zuul.conf`` with the form
``[connection NAME]``. For example, a connection to a gerrit server
may appear as:
.. code-block:: ini
[connection mygerritserver]
driver=gerrit
server=review.example.com
Zuul needs to use a single connection to look up information about
changes hosted by a given system. When it looks up changes, it will
do so using the first connection it finds that matches the server name
it's looking for. It's generally best to use only a single connection
for a given server, however, if you need more than one (for example,
to satisfy unique reporting requirements) be sure to list the primary
connection first as that is what Zuul will use to look up all changes
for that server.
|