The example Python code had wrong indentation, and wouldn't actually
work if naively copy-pasted. Noticed by Noam Hasson.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190929091440.28042-1-nyh@scylladb.com>
A documentation file that is intended to be a place for anything
debugging related: getting started tutorial, tips and tricks and
advanced guides.
For now it contains a short introductions, some selected links to
more in-depth documentation and some trips and tricks that I could think
off the top of my head.
One of those tricks describes how to load cores obtained from
relocatable packages inside the `dbuild` container. I originally
intended to add that to `tools/toolchain/README.md` but was convinced
that `docs/debugging.md` would be a better place for this.
Signed-off-by: Botond Dénes <bdenes@scylladb.com>
Message-Id: <20190924133110.15069-1-bdenes@scylladb.com>
This patch adds a getting started document for alternator,
it explains how to start up a cluster that has an alternator
API port open and how to test that it works using either an
application or some simple and minimal python scripts.
The goal of the document is to get a user to have an up and
running docker based cluster with alternator support in the
shortest time possible.
As part of trying to make alternator more accessible
to users, we expect more documents to be created so
it seems like a good idea to give all of the alternator
docs their own directory.
This adds a "alternator-address" and "alternator-port" configuration
options to the Docker image, so people can enable Alternator with
"docker run" with:
docker run --name some-scylla -d <image> --alternator-port=8080
Message-Id: <20190902110920.19269-1-penberg@scylladb.com>
Add a link to a longer document (currently, around 40 pages) about
DynamoDB's features and how we implemented or may implement them in
Alternator.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190825121201.31747-2-nyh@scylladb.com>
This adds a new document, docs/alternator.md, about Alternator.
The scope of this document should be expanded in the future. We begin
here by introducing Alternator and its current compatibility level with
Amazon DynamoDB, but it should later grow to explain the design of Alternator
and how it maps the DynamoDB data model onto Scylla's.
Whether this document should remain a short high-level overview, or a long
and detailed design document, remains an open question.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190805085340.17543-1-nyh@scylladb.com>
Recently we started to use more the concept of metric labels - several
metrics which share the same name, but differ in the value of some label
such a "group" (for different scheduling groups).
This patch documents this feature in docs/metrics.md, gives the example of
scheduling groups, and explains a couple more relevant Promethueus syntax
tricks.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190909113803.15383-1-nyh@scylladb.com>
This clarifies that "rows" are clustering rows and that there is no
information about individual collection elements.
The patch also documents some properties common to all these tables.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
Message-Id: <20190820171204.48739-1-espindola@scylladb.com>
This documents the steps needed to build Scylla's Linux packages with
the relocatable package infrastructure we use today.
Message-Id: <20190807134017.4275-1-penberg@scylladb.com>
The intention is just to document what is currently done. If someone
wants to propose changes, that can be done after the current practices
have been documented.
Signed-off-by: Rafael Ávila de Espíndola <espindola@scylladb.com>
Message-Id: <20190524135109.29436-1-espindola@scylladb.com>
Prometheus needs to remember which "instance" (node) each measurement
came from. But it doesn't actually need Scylla to tell it the instance
name - it knows which node it got each measurement from.
After Seastar commit 79281ef287
which fixed Seastar issue https://github.com/scylladb/seastar/issues/477,
the "instance" label on measurements no longer comes from Scylla but rather
is added by Prometheus. This patch corrects the documentation to explain the
current situation, instead of incorrectly saying that Scylla adds the
"instance" label itself.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190602074629.14336-1-nyh@scylladb.com>
" from Asias
Some of the function names are not updated after we change the rpc verb
names. Rename them to make them consistent with the rpc verb names.
* seastar-dev.git asias/row_level_repair_rename_consistent_with_rpc_verb/v1:
repair: Rename request_sync_boundary to get_sync_boundary
repair: Rename request_full_row_hashes to get_full_row_hashes
repair: Rename request_combined_row_hash to get_combined_row_hash
repair: Rename request_row_diff to get_row_diff
repair: Rename send_row_diff to put_row_diff
repair: Update function name in docs/row_level_repair.md
docs/metrics.md so far explained just the REST API for retrieving current
metrics from a single Scylla node. In this patch, I add basic explanations
on how to use the Prometheus and Grafana tools included in the
"scylla-grafana-monitoring" project.
It is true that technically, what is being explained here doesn't come
with the Scylla project and requires the separate scylla-grafana-monitoring
to be installed as well. Nevertheless, most Scylla developers will need this
knowledge eventually and suprisingly it appears it was never documented
anywhere accessible to newbie developers, and I think metrics.md is the
right place to introduce it.
In fact, I myself wasn't aware until today that Prometheus actually had
its own Web UI on port 9090, and that it is probably more useful for
developers than Grafana is.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Reviewed-by: Botond Denes <bdenes@scylladb.com>
Message-Id: <20190129114214.17786-1-nyh@scylladb.com>
Start a new document with an overview of isolation in Scylla, i.e.,
scheduling groups, I/O priority classes, controllers, etc.
As all documents in docs/, this is a document for developers (not users!)
who need to understand how isolation between different pieces of Scylla
(e.g., queries, compaction, repair, etc.) works, which scheduling groups
and I/O classes we have and why, etc.
The document is still very partial and includes a lot of TODOs on
places where the explanation needs to be expanded. In particular it
needs an accurate explanation (and not just a name) of what kind of
work is done under each of the groups and classes, and an explanation
of how we set up RPC to use which scheduling groups for the code it
executes.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190103183232.21348-1-nyh@scylladb.com>
While we keep ordinary hints in a directory parallel to the data directory,
we decided to keep the materialized view hints in a subdirectory of the data
directory, named "view_pending_updates". But during boot, we expect all
subdirectories of data/ to be keyspace names, and when we notice this one,
we print a warning:
WARN: database - Skipping undefined keyspace: view_pending_updates
This spurious warning annoyed users. But moreover, we could have bigger
problems if the user actually tries to create a keyspace with that name.
So in this patch, we move the view hints to a separate top-level directory,
which defaults to /var/lib/scylla/view_hints, but as usual can be configured.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190107142257.16342-1-nyh@scylladb.com>
Various small improvements to docs/logging.md:
1. Describe the options to log to stdout or syslog and their defaults.
2. Mention the possibility of using nodetool instead of REST API.
3. Additional small tweaks to formatting.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190106111851.26700-1-nyh@scylladb.com>
Add a new document about logging in Scylla, and how to change the log levels
when running Scylla and during the run.
It needs more developer-oriented information (e.g., how to create new logger
subsystems in the code) but I think it's a good start.
Some of the text is based on Glauber's writeup for the Scylla website on
changing log levels at runtime.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190106103606.26032-1-nyh@scylladb.com>
BYPASS CACHE was mistakenly documenting an earlier version of the patch.
Correct it to document th committed version.
Message-Id: <20181126125810.9344-1-avi@scylladb.com>
Today I realised that although we have per-table metrics, they are not
*really* available by default. I was suprised to find that we don't have
(as far as I can tell) a document explaining why it is so, or how to enable
them anyway. Moreover, the more I investigated this issue, the more I
realised how little I know on Scylla's metrics - how they are calculated,
how they are collected, their different types, and so on.
So I sat down to figure out everything I wanted to learn about Scylla metrics,
and then wrote it all down in a new document, docs/metrics.md.
There are some missing pieces in this document marked by TODO, and probably
additional missing pieces that I'm not aware of, but I think this is already
a good start and can be (and should be) improved-on later.
We really need to have more of these documents describing various Scylla
subsystems to new developers - what each subsystem does, why it does what
it does, where is the code, and so on. I am facing these problems every
day as a seasoned developer - I can't even imagine what our new developers
face when trying to understand a subsystem they are not yet familiar with.
Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20180920131103.20590-1-nyh@scylladb.com>
For some reason the doc entry for large_partitions was outdated.
It contained incorrect ORDERING information and wrong usage example,
since large_partitions' schema changed multiple times during
the reviewing process.
Message-Id: <1910f270419536ebccffde163ec1bfc67d273306.1533128957.git.sarna@scylladb.
com>
By default Scylla docker runs without the security features.
This patch adds support for the user to supply different params values for the
authenticator and authorizer classes and allowing to setup a secure Scylla in
Docker.
For example if you want to run a secure Scylla with password and authorization:
docker run --name some-scylla -d scylladb/scylla --authenticator
PasswordAuthenticator --authorizer CassandraAuthorizer
Update the Docker documentation with the new command line options.
Signed-off-by: Noam Hasson <noam@scylladb.com>
Message-Id: <20180620122340.30394-1-noam@scylladb.com>
By default, overprovisioned is not enabled on docker unless it is
explicitly set. I have come to believe that this is a mistake.
If the user is running alone in the machine, and there are no other
processes pinned anywhere - including interrupts - not running
overprovisioned is the best choice.
But everywhere else, it is not: even if a user runs 2 docker containers
in the same machine and statically partitions CPUs with --smp (but
without cpuset) the docker containers will pin themselves to the same
sets of CPU, as they are totally unaware of each other.
It is also very common, specially in some virtualized environments, for
interrupts not to be properly distributed - being particularly keen on
being delivered on CPU0, a CPU which Scylla will pin by default.
Lastly, environments like Kubernetes simply don't support pinning at the
moment.
This patch enables the overprovisioned flag if it is explicitly set -
like we did before - but also by default unless --cpuset is set.
Signed-off-by: Glauber Costa <glauber@scylladb.com>
Message-Id: <20180331142131.842-1-glauber@scylladb.com>
