Adding upstream version 2:4.20.0+dfsg.upstream/2%4.20.0+dfsg

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 137 insertions, 0 deletions

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+Selftest target environments (testenvs)
+=======================================
+Samba's integration testing heavily relies on the automatic creation of a Samba
+network. This specialized test environment is generally referred to as a Samba
+'testenv'.
+
+A testenv involves starting the Samba server listening on a fake network, which
+is established using the socket_wrapper library from cwrap (https://cwrap.org).
+All testing is also done as a non-root user using the uid_wrapper library, also
+from cwrap.
+
+Samba's test framework uses many different types of testenv. Each testenv is
+customized to test a particular Samba feature or configuration. Using cwrap
+allows multiple different Samba servers to run at the same time, without
+interference.
+
+Some of the different testenvs are described in more detail below.
+
+Important notes if adding a new testenv
+---------------------------------------
+- When adding a new testenv, in the Perl code it is recommended to always
+explicitly specify the --configfile option in the samba-tool command, i.e. add
+"env->{CONFIGURATION}" to the samba-tool command. Otherwise, the samba-tool
+can try to load smb.conf from the default install location (i.e.
+/usr/local/samba/etc/smb.conf). Loading a host-specific smb.conf that's outside
+of the testenv is obviously not ideal and something we want to avoid in a
+reliable test framework.
+
+'local' disambiguation
+----------------------
+You may notice some variation in the target testenv that test suites are run
+against, for example "ad_dc" and "ad_dc:local". The main difference is the
+":local" changes the smb.conf that the testenv uses. By default, the testenvs
+use the st/client/client.conf config-file, so that they simulate a client
+talking to the Samba server. However, some tests may want to simulate running
+a command on the Samba server itself. In these cases, the ":local" is used,
+which means the testenv uses the Samba server's smb.conf instead (i.e.
+st/ad_dc/etc/smb.conf).
+
+Note that several of the testenvs also use local in their name, e.g.
+'localvampiredc'. In particular, there's the 'localdc', which is the NetBIOS
+name of the DC in the 'ad_dc_ntvfs' testenv.
+
+dns_hub
+-------
+dns_hub doesn't run a Samba/smbd server like the other testenvs do. It's there
+to solve the problem of how to do DNS more nicely in selftest. Running
+autobuild can start up a lot of different testenvs, and so we end up with
+different DCs running in different domains. Each test suite only wants to talk
+to a specific domain at a time. However, by default the tests all use a common
+client.conf - essentially the tests are simulating a single client that's
+pretending to be in several different domains. The problem is when the test
+wants to resolve a DNS host, which DC should it ask? Each DC only knows about its
+own realm. dns_hub.py acts as a proxy, so it works out the correct DC to forward
+the query to, based on the queried host's realm.
+
+Vampire DC
+----------
+Vampire DC gets its name for historic reasons. It's one of the few testenvs
+where 2 DCs are joined together, so it's used for a lot of DRS replication
+testing. Basically its main job is to 'suck' the database changes out of
+another DC (the 'ad_dc_ntfvs' DC).
+
+There's also a 'vampire_2000_dc' that joins the 'fl2000dc' DC, although that's
+not used very much.
+
+Backup/restore testenvs
+-----------------------
+Several testenvs are created to test the domain backup/restore commands. These
+testenvs verify that we can backup and restore a domain's database, start
+Samba against it, and the restored database is actually functional. There are
+several different flavours of backups (to cover different use-cases), so there
+are separate testenvs for each one.
+
+- backupfromdc: A fairly plain AD DC used as the base to generate the
+    backup-files. These backup-files will then seed the domain database
+    for the separate testenvs below.
+    Backupfromdc's other unique feature is that it's the only testenv that gets
+    provisioned with a non-default site, i.e. Default-First-Site-Name doesn't
+    exist.
+- restoredc: tests the 'backup online' option. Online backups are similar to
+    doing a DC join.
+    Restoredc's other unique feature is that is has SMBv1 disabled.
+- offlinebackupdc: tests the 'backup offline' option. Offline backups capture
+    the raw DB files on disk (safely).
+- renamedc: tests the 'backup rename' option, where the domain and realm are
+    renamed.
+- labdc: one of the use-cases for the backup tool is to create a realistic
+    pre-production testbed, based off a production DC. This testenv simulates
+    that process. It uses the 'backup rename --no-secrets' option.
+
+customdc testenv
+----------------
+The customdc is a special testenv that's only used for manual testing, rather
+than the automated tests most testenvs are primarily used for.
+
+The customdc testenv also uses the backup/restore tool, however, it is quite
+special. Instead of the backup-file being automatically generated from a
+vanilla AD DC (i.e. backupfromdc), you can specify any backup-file you like.
+
+To run the testenv, you need to specify a 'BACKUP_FILE' shell variable, e.g.
+
+BACKUP_FILE=/tmp/samba-backup-50k-dc-0-mdb-50k-offline.tar.bz2 \
+    SELFTEST_TESTENV=customdc make testenv
+
+The main use-case for the customdc is testing changes against a large
+database. Adding users is very time-consuming, so it's much quicker to populate
+a domain with users once, take a backup, and then you can spin up a testenv
+based on the backup multiple times.
+
+Another use-case is that if you get a database that's corrupted or in a bad
+state, then you could save a backup and be able to easily get the database back
+into the bad state. This allows you to try different commands to diagnose/fix
+the issue, without fear of never seeing the problem again.
+
+You could even spin up a 'lab DC' inside a testenv, by taking a backup of a
+real network DC.
+
+preforkrestartdc testenv
+------------------------
+Used to test killing and restarting processes under the pre-fork model. Due to
+the destructive nature of the tests, it's not recommended to use this testenv
+for anything else.
+
+proclimitdc testenv
+-------------------
+Used to test process limits on the standard model. It sets the number of
+allowed processes artificially low, to test that new connections are refused
+correctly.  Due to the limited number of connections accepted, it's not
+recommended to use this testenv for anything else.
+
+schema_dc
+----------------
+This is a 2-DC testenv setup (schema_dc and schema_pair_dc).
+We provision the first DC, and join the second, using an older version of the
+schema (2008R2), then start-up Samba. Then, we run a schema upgrade (i.e.
+'samba-tool domain schemaupgrade') on the PDC.