All lambdas passed to test_using_reusable_sst() and
test_using_reusable_sst_returning() have been converted to future::get()
calls (according to the seastar::thread context that they are now executed
in). None of the lambdas return futures anymore; they all directly return
void or non-void. Therefore, drop futurize_invoke(...).get() around the
lambda invocations in test_using_reusable_sst*().
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
For better readability, replace the future::then() chaining (and the
associated manual fiddling with object lifecycles) with future::get() (and
rely on seastar::thread's stack). We're already in seastar::thread
context.
Similarly, replace the future::finally() underlying with_closeable() with
deferred_close(); with the assumption that mutation_reader::close() never
fails (and is therefore safe to call in the "deferred_close" destructor).
This is actually guaranteed, as mutation_reader::close() is marked
"noexcept".
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
According to early patch "test/sstable: rewrite test_using_reusable_sst()
with async" in this series, lambdas passed to test_using_reusable_sst()
are invoked:
(a) less importantly here, in seastar::thread context,
(b) more importantly here, futurized (temporarily so).
The test case not_find_key_composite_bucket0() doesn't chain futures;
therefore it needs no conversion to future::get() for purpose (a);
however, we can eliminate its empty future return. Fact (b) will cover for
that, until all such lambdas are converted to direct "void" returns (at
which point we can remove the futurization from
test_using_reusable_sst()).
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
For better readability, replace future::then() chaining with
future::get(). (We're already in seastar::thread context.)
This patch is best viewed with "git show -b".
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
According to early patch "test/sstable: rewrite test_using_reusable_sst()
with async" in this series, lambdas passed to test_using_reusable_sst()
are invoked:
(a) less importantly here, in seastar::thread context,
(b) more importantly here, futurized (temporarily so).
The test cases find_key_map(), find_key_set(), find_key_list(),
find_key_composite(), all_in_place() don't chain futures; therefore they
need no conversion to future::get() for purpose (a); however, we can
eliminate their empty future returns. Fact (b) will cover for that, until
all such lambdas are converted to direct "void" returns (at which point we
can remove the futurization from test_using_reusable_sst()).
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
All three lambdas passed to write_and_validate_sst() now use future::get()
rather than future::then() chaining; in other words, the future::get()
calls inside all these seastar::thread contexts have been pushed down to
the lambdas. Change all these lambdas' return types from future<> to void.
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
The lambda passed to write_and_validate_sst() already runs in
seastar::thread context; replace future::then() chaining with
future::get() calls.
We're going to eliminate the trailing "return make_ready_future<>()"
later.
This patch is best viewed with "git show -W -b".
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
The lambda passed to write_and_validate_sst() already runs in
seastar::thread context; replace future::then() chaining with
future::get() calls.
We're going to eliminate the trailing "return make_ready_future<>()"
later.
This patch is best viewed with "git show -W -b".
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
The lambda passed to write_and_validate_sst() already runs in
seastar::thread context; replace future::then() chaining with
future::get() calls.
We're going to eliminate the trailing "return make_ready_future<>()"
later.
This patch is best viewed with "git show -W -b".
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
check_component_integrity() does not rely on any deferred close or stop
operations; turn it into a coroutine therefore, for best readability.
This conversion demonstrates particularly well how much the stack eases
coding. We no longer need to artificially extend the lifetime of "tmp"
with a final
.then([tmp] {})
future. Consequently, "tmp" no longer needs to be a shared pointer to an
on-heap "tmpdir" object; "tmp" can just be a "tmpdir" object on the stack.
While at it, eliminate the single-use local objects "s" and "gen", for
movability's sake. (We could use std::move() on these variables, but it
seems easier to just flatten the function calls that produce the
corresponding rvalues into the write_sst_info() argument list.)
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
The lambda passed to test_using_reusable_sst() is now invoked --
futurized, transitorily -- in seastar::thread context; stop returning an
explicit make_ready_future<>() from the lambda.
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
summary_query_fail() does not rely on any deferred close or stop
operations; turn it into a coroutine therefore, for best readability.
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
simple_index_read() and composite_index_read() do not rely on any deferred
close or stop operations; turn them into coroutines therefore, for best
readability.
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
Improve the readability of test_using_reusable_sst() by replacing
future::then() chaining with test_env::do_with_async() and future::get().
Unlike seastar::async(), test_env::do_with_async() restricts its input
lambda to returning "void". Because of this, introduce the variant
test_using_reusable_sst_returning(), based on
test_env::do_with_async_returning(), for lambdas returning non-void. Put
the latter to use in index_read() at once.
Subsequently, we'll gradually convert the lambdas passed to
test_using_reusable_sst() and test_using_reusable_sst_returning() from
returning futures to returning direct values. In order for
test_using_reusable_sst() and test_using_reusable_sst_returning() to cope
with both types of lambdas, wrap the lambdas into futurize_invoke().get().
In the seastar::thread context, future::get() will gracefully block on
genuine futures, and return immediately on direct values that were
futurized on the spot.
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
Make test_using_working_sst() easier to read by:
(1) replacing test_env::do_with() with seastar::async(),
seastar::defer(), and future::get();
(2) replacing seastar::async() and seastar::defer() with
test_env::do_with_async().
Technically speaking, this change does not perfectly preserve exceptional
behavior. Namely, test_env::do_with() uses future::finally() to link
test_env::stop() to the chain of futures, and future::finally() permits
test_env::stop() itself to throw an exception -- potentially leading to a
seastar::nested_exception being thrown, which would carry both the
original exception and the one thrown by test_env::stop().
Contrarily, the test_env::stop() deferred with seastar::defer() runs in a
destructor, and therefore test_env::stop() had better not throw there.
However, we will assume that test_env::stop() does not throw, albeit not
marked "noexcept". Prior commits 8d704f2532 ("sstable_test_env:
Coroutinize and move to .cc test_env::stop()", 2023-10-31) and
2c78b46c78 ("sstables::test_env: Carry compaction manager on board",
2023-10-31) show that we've considered individual actions in
test_env::stop() not to throw before.
The 128KB stack of seastar::thread (which underlies seastar::async())
should be a tolerable cost in a test case, in exchange for the improved
readability.
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
Currently when a partition is deleted from the base table, we generate a
row tombstone update for each one of the view rows in the partition.
When the partition key in the view is the same as the base, maybe in a
different order, this can be done more efficiently - The whole corresponding
view partition can be deleted with one partition tombstone update.
With this commit, when generating view updates, if the update mutation has a
partition tombstone then for the views which have the same partition key
we will generate a partition tombstone update, and skip the individual
row tombstone updates.
Fixesscylladb/scylladb#8199Closesscylladb/scylladb#19338
* github.com:scylladb/scylladb:
mv: skip reading rows when generating partition tombstone update
mv: delete a partition in a single operation when applicable
cql-pytest: move ScyllaMetrics to util file to allow reuse
Tablet load balancer tries to equalize tablet load between shards by
moving tablets. Currently, the tablet load balancer assumes that each
tablet has the same hotness. This may not be true, and some tables may
be hotter than others. If some nodes end up getting more tablets of
the hot table, we can end up with request load imbalance and reduced
performance.
In 79d0711c7e we implemented a
mitigation for the problem by randomly choosing the table whose tablet
replica should be moved. This should improve fairness of
movement. However, this proved to not be enough to get a good
distribution of tablets.
This change improves candidate selection to not relay on randomness
but rather evaluating candidates with respect to the impact on load
imbalance. Also, if there is no good candidate, we consider picking
other source shards, not the most-loaded one. This is helpful because
when finishing node drain we get just a few candidates per shard, all
of which may belong to a single table, and the destination may already
be overloaded with that table. Another shard may contain tablets of
another table which is not yet overloaded on the destination. And
shards may be of similar load, so it doesn't matter much which shard
we choose to unload.
We also consider other destinations, not the least-loaded one. This
helps when draining nodes and the source node has few shard
candidates. Shards on the destination may have similar load so there
is more than one good destinatin candidate. By limiting ourselves to a
single shard, we increase the chance that we're overload the table on
that shard.
The algorithm was evaluated using "scylla perf-load-balancing", which
simulates a sequeunce of 8 node bootstraps and decommissions for
different node and shard counts, RF, and tablet counts.
For example, for the following parameters:
params: {iterations=8, nodes=5, tablets1=128 (2.4/sh), tablets2=512 (9.6/sh), rf1=3, rf2=3, shards=32}
The results are:
Before:
Overcommit (old) : init : {table1={shard=1.25 (best=1.25), node=1.00}, table2={shard=1.04 (best=1.04), node=1.00}}
Overcommit (old) : worst: {table1={shard=4.00 (best=1.25), node=1.81}, table2={shard=1.25 (best=1.04), node=1.11}}
Overcommit (old) : last : {table1={shard=2.50 (best=1.25), node=1.41}, table2={shard=1.25 (best=1.04), node=1.05}}
After:
Overcommit : init : {table1={shard=1.25 (best=1.25), node=1.00}, table2={shard=1.04 (best=1.04), node=1.00}}
Overcommit : worst: {table1={shard=1.50 (best=1.25), node=1.02}, table2={shard=1.12 (best=1.04), node=1.01}}
Overcommit : last : {table1={shard=1.25 (best=1.25), node=1.00}, table2={shard=1.04 (best=1.04), node=1.00}}
So worst shard overcommit for table1 was reduced from 4 to 1.5. Overcommit
of 4 means that the most-loaded shard has 4 times more tablets than
the average per-shard load in the cluster.
Also, node overcommit for table1 was reduced from 1.81 to 1.02.
The magnitude of improvement depends greatly on test configurtion, so on topology and tablet distribution.
The algorithm is not perfect, it finds a local optimum. In the above
test, overcommit of 1.5 is not the best possible (1.25).
One of the reason why the current algorithm doesn't achieve best
distribution is that it works with a single movement at a time and
replication constraints limit the choice of destinations. Viable
destinations for remaining candidates may by only on nodes which are
not least-loaded, and we won't be able to fill the least loaded
node. Doing so would require more complex movement involving moving a
tablet from one of the destination nodes which doesn't have a replica
on the least loaded node and then replacing it with the candidate from
the source node.
Another limitation is that the algorithm can only fix balance by
moving tablets away from most loaded nodes, and it does so due to
imbalance between nodes. So it cannot fix the imbalance which is
already present on the nodes if there is not much to move due to
similar load between nodes. It is designed to not make the imbalance
worse, so it works good if we started in a good shape.
Fixes https://github.com/scylladb/scylladb/issues/16824Closesscylladb/scylladb#19779
* github.com:scylladb/scylladb:
test: perf: tablet_load_balancing: Test with higher shard and tablet counts
tablets: load_balancer: Avoid quadratic complexity when finding best candidate
tablets: load_balancer: Maintain load sketch properly during intra-node migration
tablets: load_balancer: Use "drained" flag
test: perf: tablet_load_balancing: Report load balancer stats
tablets: load_balancer: Move load_balancer_stats_manager to header file
tablets: load_balancer: Split evaluate_candidate() into src and dst part
tablets: load_balancer: Optimize evaluate_candidate()
tablets: load_balancer: Add more statistics
tablets: load_balancer: Track load per table on cluster level
tablets: load_balancer: Track load per table on node level
tablets: load_balancer: Use a single load sketch for tracking all nodes
locator: load_sketch: Introduce populate_dc()
tablets: load_balancer: Modify target load sketch only when emitting migration
locator: load_sketch: Introduce get_most_loaded_shard()
locator: load_sketch: Introduce get_least_loaded_shard()
locator: load_sketch: Optimize pick()/unload()
locator: load_sketch: Introduce load_type
test: perf: tablet_load_balancing: Report total tablet counts
test: perf: tablet_load_balancing: Print run parameters in the single simulation case too
test: perf: tablet_load_balancing: Report time it took to schedule migrations
tablets: load_balancer: Log table load stats after each migration
tablets: load_balancer: Log per-shard load distribution in debug level
tablets: load_balancer: Improve per-table balance
tablets: load_balancer: Extract check_convergence()
tablets: load_balancer: Extract nodes_by_load_cmp
tablets: load_balancer: Maintain tablet count per table
tablets: load_balancer: Reuse src_node_info
test: perf: tablet_load_balancing: Print warnings about bad overcommit
test: perf: tablet_load_balancing: Allow running a single simulation
test: perf: tablet_load_balancing: Report best possible shard overcommit
test: perf: tablet_load_balancing: Report global shard overcommit
It's only needed to start hints via proxy, but proxy can do it without gossiper argument
Closesscylladb/scylladb#19894
* github.com:scylladb/scylladb:
storage_service: Remote gossiper argument from join_cluster()
proxy: Use remote gossiper to start hints resource manager
hints: Const-ify gossiper references and anchor pointers
A user complained that ScyllaDB is incompatible with Cassandra when it
requires ALLOW FILTERING on a restriction like WHERE x=1 AND y=1 where
x and y are two columns with secondary indexes.
In the tests added in this patch we show that:
1. Scylla *is* compatible with Cassandra when the traditional "CREATE
INDEX" is used - ALLOW FILTERING *is* required in this case in both
Cassandra and Scylla.
2. If SAI is used in Cassandra (CREATE CUSTOM INDEX USING 'SAI'),
indeed ALLOW FILTERING becomes optional. I believe this is incorrect
so I opened CASSANDRA-19795.
These two tests combined show that we're not incompatible with Cassandra,
rather Cassandra's two index implementations are incompatible between
themselves, and Scylla is in fact compatible in this case with Cassadra's
traditional index and not with SAI.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closesscylladb/scylladb#19909
Rather than maximum per-node shard overcommit. Global shard overcommit
is a better metric since we want to equalize global load not just
per-node load.
Most callers of the raft group0 client interface are passing a real
source instance, so we can use the abort source reference in the client
interface. This change makes the code simpler and more consistent.
The Alternator command ListTables is supposed to list actual tables
created with CreateTable, and should list things like materialized views
(created for GSI or LSI) or CDC log tables.
We already properly excluded materialized views from the list - and
had the tests to prove it - but forgot both the exclusion and the testing
for CDC log tables - so creating a table xyz with streams enable would
cause ListTables to also list "xyz_scylla_cdc_log".
This patch fixes both oversights: It adds the code to exclude CDC logs
from the output of ListTables, add adds a test which reproduces the bug
before this fix, and verifies the fix works.
Fixes#19911.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closesscylladb/scylladb#19914
In commit bac7c33313 we introduced a new
test for the Alternator "/localnodes" request, checking that a node
that is still joining does not get returned. The tests used what I
thought were "very high" timeouts - we had a timeout of 10 seconds
for starting a single node, and injected a 20 second sleep to leave
us 10 seconds after the first sleep.
But the test failed in one extremely slow run (a debug build on
aarch64), where starting just a single node took more than 15 seconds!
So in this patch I increase the timeouts significantly: We increase
the wait for the node to 60 seconds, and the sleeping injection to
120 seconds. These should definitely be enough for anyone (famous
last words...).
The test doesn't actually wait for these timeouts, so the ridiculously
high timeouts shouldn't affect the normal runtime of this test.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Closesscylladb/scylladb#19916
There's a test in object_store suite that verifies the contents of a bucket. It does with the plain http request, but unfortunately this doesn't work -- even local minio uses restricted bucket and using plain http request results in 403(Forbidden) error code. Test doesn't check it and continues working with empty list of objects which, in turn, is what it expects to see.
The fix is in using boto3. With it, the acc/secret pair is picked up and listing the bucket finally works.
Closesscylladb/scylladb#19889
* github.com:scylladb/scylladb:
test/object_store: Use boto3.resource to list bucket
test/object_store: Add get_s3_resource() helper
Instead of plain http request, use the power of boto3 package. The
recently added get_s3_resource() facilitates creating one
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
It creates boto3.resource object that points to endpoint maintained
by s3_server argument (that tests obtain via fixture). This allows
using boto3 to access S3 bucket from local minio server.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Currently, delete_atomically can be called with
a list of sstables from mixed prefixes in two cases:
1. truncate: where we delete all the sstables in the table directory
2. tablet cleanup: similar to truncate but restricted to sstables in a
single tablet replica
In both cases, it is possible that sstables in staging (or quarantine)
are mixed with sstables in the base directory.
Until a more comprehensive fix is in place,
(see https://github.com/scylladb/scylladb/pull/19555)
this change just lifts the ban on atomic deletion
of sstables from different prefixes, and acknowledging
that the implementation is not atomic across
prefixes. This is better than crashing for now,
and can be backported more easily to branches
that support tablets so tablet migration can
be done safely in the presence of repair of
tables with views.
Refs scylladb/scylladb#18862
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Closesscylladb/scylladb#19816
This pointer was only needed to pull all the way down the hints resource
manager start() method. It's no longer needed for that.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
The testcase `test_bloom_filter_reclaim_during_reload` checks the
SSTable manager's `_total_memory_reclaimed` against an expected value to
verify that a Bloom filter was reloaded. However, it does not wait for
the manager to update the variable, causing the check to fail if the
update has not occurred yet. Fix it by making the testcase wait until
the variable is updated to the expected value.
Fixes#19879
Signed-off-by: Lakshmi Narayanan Sreethar <lakshmi.sreethar@scylladb.com>
Closesscylladb/scylladb#19883
When a node that is permanently down is replaced, it is marked as "left" but it still can be a replica of some tablets. We also don't keep IPs of nodes that have left and the `node` structure for such node returns an empty IP (all zeros) as the address.
This interacts badly with the view update logic. The base replica paired with the left node might decide to generate a view update. Because storage proxy still uses IPs and not host IDs, it needs to obtain the view replica's IP and tell the storage proxy to write a view update to that node - so, it chooses 0.0.0.0. Apparently, storage proxy decides to write a hint towards this address - hinted handoff on the other hand operates on host IDs and not IPs, so it attempts to translate the IP back, which triggers an assertion as there is no replica with IP 0.0.0.0.
As a quick workaround for this issue just drop view updates towards nodes which seem to have IPs that are all zeros. It would be more proper to keep the view updates as hints and replay them later to the new paired replica, but achieving this right now would require much more significant changes. For now, fixing a crash is more important than keeping views consistent with base replicas.
In addition to the fix, this PR also includes a regression test heavily based on the test that @kbr-scylla prepared during his investigation of the issue.
Fixes: scylladb/scylladb#19439
This issue can cause multiple nodes to crash at once and the fix is quite small, so I think this justifies backporting it to all affected versions. 6.0 and 6.1 are affected. No need to backport to 5.4 as this issue only happens with tablets, and tablets are experimental there.
Closesscylladb/scylladb#19765
* github.com:scylladb/scylladb:
test: regression test for MV crash with tablets during decommission
db/view: drop view updates to replaced node marked as left
Currently when a partition is deleted from the base table, we generate a
row tombstone update for each one of the view rows in the partition.
When the partition key in the view is the same as the base, maybe in a
different order, this can be done more efficiently - The whole corresponding
view partition can be deleted with one partition tombstone update.
With this commit, when generating view updates, if the update mutation has a
partition tombstone then for the views which have the same partition key
we will generate a partition tombstone update, and skip the individual
row tombstone updates.
Fixesscylladb/scylladb#8199
ScyllaMetrics is a useful generic component for retrieving metrics in a
pytest.
The commit moves the implementation from test_shedding.py to util.py to
make it reusable in other tests in cql-pytest.
The admission test has a section which tests admission when the
semaphore has inactive reads. This section (and therefore the enire
test) became flaky lately, after a seemingly unrelated seastar upgrade,
which improved timers.
The cause of the flakyness is the permit which is made inactive later:
this permit is created with 0 timeout (times out immediately). For some
time now, when the timeout timer of a permit fires, if the permit is
inactive, it is evicted. This is what makes the test fail: the inactive
read times out and ends up evicting this permit, which is not expected
for the test. The reason this was not a problem before, is that the test
finishes very quickly, usually, before the timer could even be polled by
the reactor. The recent seastar changes changed this and now the timer
sometimes get polled and fires, failing the test.
Fixes: #19801Closesscylladb/scylladb#19859
Alternator allows authentication into the existing CQL roles, but
roles which have the flag "login=false" should be refused in
authentication, and this patch adds the missing check.
The patch also adds a regression test for this feature in the
test/alternator test framework, in a new test file
test/alternator/cql_rbac.py. This test file will later include more
tests of how the CQL RBAC commands (CREATE ROLE, GRANT, REVOKE)
affect authentication and authorization in Alternator.
In particular, these tests need to use not just the DynamoDB API but
also CQL, so this new test file includes the "cql" fixture that allows
us to run CQL commands, to create roles, to retrieve their secret keys,
and so on.
Fixesscylladb/scylladb#19735Closesscylladb/scylladb#19740
Introduce virtual tasks - task manager tasks which cover
cluster-wide operations.
Virtual tasks aren't kept in memory, instead their statuses
are retrieved from associated service when user requests
them with task manager API. From API users' perspective,
virtual tasks behave similarly to regular tasks, but they can
be queried from any node in a cluster.
Virtual tasks cannot have a parent task. They can have
children on each node in a cluster, but do not keep references
to them. So, if a direct child of a virtual task is unregistered
from task manager, it will no longer be shown in parent's
children vector.
virtual_task class corresponds to all virtual tasks in one
group. If users want to list all tasks in a module, a virtual_task
returns all recent supported operations; if they request virtual
task's status - info about the one specified operation is
presented. Time to live, number of tracked operations etc.
depend on the implementation of individual virtual_task.
All virtual_tasks are kept only on shard 0.
Refs: https://github.com/scylladb/scylladb/issues/15852
New feature, no backport needed.
Closesscylladb/scylladb#16374
* github.com:scylladb/scylladb:
docs: describe virtual tasks
db: node_ops: filter topology request entries
test: add a topology suite for testing tasks
node_ops: service: create streaming tasks
node_ops: register node_ops_virtual_task in task manager
service: node_ops: keep node ops module in storage service
node_ops: implement node_ops_virtual_task methods
db: service: modify methods to get topology_requests data
db: service: add request type column to topology_requests
node_ops: add task manager module and node_ops_virtual_task
tasks: api: add virtual task support to get_task_status_recursively
tasks: api: add virtual task support
tasks: api: add virtual tasks support to get_tasks
tasks: add task_handler to hide task and virtual_task differences from user
tasks: modify invoke_on_task
tasks: implement task_manager::virtual_task::impl::get_children
tasks: keep virtual tasks in task manager
tasks: introduce task_manager::virtual_task
We modify `ScyllaCluster.server_start` so that it changes seeds of the
starting node to all currently running nodes. This allows writing tests like
```python
s1 = await manager.server_add(start=False)
await manager.server_add()
await manager.server_start(s1.server_id)
```
However, it disallows writing tests that start multiple clusters. To fix this,
we add the `seeds` parameter to `server_start`.
We also improve the logic in `ScyllaCluster.add_server` to allow writing
tests like
```python
await manager.server_add(expected_error="...")
await manager.server_add()
```
This PR only adds improvements to the `test.py` framework, no need
to backport it.
Closesscylladb/scylladb#19847
* github.com:scylladb/scylladb:
test: scylla_cluster: improve expected_error in add_server
test: scylla_cluster: support more test scenarios
test: scylla_cluster: correctly change seeds in server_start
We make two changes:
- we lease the IP address of a node that failed to boot because of
an expected error,
- we don't log "Cluster ... added ..." when a node fails to boot
because of an expected error.
