When multiple primary nodes fail simultaneously, the cluster can not recover
within the default effective time (data_age limit). The main reason is that
the vote is without ranking among multiple replica nodes, which case too many
epoch conflicts.
Therefore, we introduced into ranking based on the failed primary shard-id.
Introduced a new failed_primary_rank var, this var means the rank of this
myself instance in the context of all failed primary list. This var will be
used in failover and we will do the failover election packets in order based
on the rank, this can effectively avoid the voting conflicts.
If a single primary is down, the behavior is the same as before. If multiple
primaries are down, their replica election initiation time will be delayed
by 500ms according to the ranking.
Signed-off-by: Binbin <binloveplay1314@qq.com>
Add `meet_sent` field in `clusterNode` indicating the last time we sent
a MEET packet. Use this field to only (re-)send a MEET packet once every
handshake timeout period when detecting a node without an inbound link.
When receiving multiple MEET packets on the same link while the node is
in handshake state, instead of dropping the packet, we now simply
prevent the creation of a new node. This way we still process the MEET
packet's gossip and reply with a PONG as any other packets.
Improve some logging messages to include `human_nodename`. Add
`nodeExceedsHandshakeTimeout()` function.
This is a follow-up to this previous PR:
https://github.com/valkey-io/valkey/pull/1307
And a partial fix to the crash described in:
https://github.com/valkey-io/valkey/pull/1436
---------
Signed-off-by: Pierre Turin <pieturin@amazon.com>
This is a follow of #1305, we now decided to apply the same change
to automatic failover as well, that is, move forward with removing
it for both automatic and manual failovers.
Quote from Ping during the review:
Note that we already debounce transient primary failures with node
timeout, ensuring failover is only triggered after sustained outages.
Election timing is naturally staggered by replica spacing, making the
likelihood of simultaneous elections from replicas of the same shard
very low. The one-vote-per-epoch rule further throttles retries and
ensures orderly elections. On top of that, quorum-based primary failure
confirmation, cluster-state convergence, and slot ownership validation
are all built into the process.
Quote from Madelyn during the review:
It against the specific primary. It's to prevent double failovers.
If a primary just took over we don't want someone else to try to
take over and give the new primary some amount of time to take over.
I have not seen this issue though, it might have been over optimizing?
The double failure mode, where a node fails and then another node fails
within the nodetimeout also doesn't seem that common either though.
So the conclusion is that we all agreed to remove it completely,
it will make the code a lot simpler. And if there is other specific
edge cases we are missing, we will fix it in other way.
See discussion #1305 for more information.
Signed-off-by: Binbin <binloveplay1314@qq.com>
In some cases, when meeting a new node, if the handshake times out, we
can end up with an inconsistent view of the cluster where the new node
knows about all the nodes in the cluster, but the cluster does not know
about this new node (or vice versa).
To detect this inconsistency, we now check if a node has an outbound
link but no inbound link, in this case it probably means this node does
not know us. In this case we (re-)send a MEET packet to this node to do
a new handshake with it.
If we receive a MEET packet from a known node, we disconnect the
outbound link to force a reconnect and sending of a PING packet so that
the other node recognizes the link as belonging to us. This prevents
cases where a node could send MEET packets in a loop because it thinks
the other node does not have an inbound link.
This fixes the bug described in #1251.
---------
Signed-off-by: Pierre Turin <pieturin@amazon.com>
This log allows us to easily distinguish between full coverage and
minority partition when the cluster fails. Sometimes it is not easy
to see the minority partition in a healthy shards (both primary and
replicas).
And we decided not to add a cluster_fail_reason field to cluster info.
Given that there are only two reasons and both are well-known and if
we ended up adding more down the road we can add it in the furture.
Signed-off-by: Binbin <binloveplay1314@qq.com>
When a node role changes, we should brocast the change to notify other nodes.
For example, one primary and one replica, after a failover, the replica became
a new primary, the primary became a new replica.
And then we trigger a second cluster failover for the new replica, the
new replica will send a MFSTART to its primary, ie, the new primary.
But the new primary may reject the MFSTART due to this logic:
```
} else if (type == CLUSTERMSG_TYPE_MFSTART) {
if (!sender || sender->replicaof != myself) return 1;
```
In the new primary views, sender is still a primary, and sender->replicaof
is NULL, so we will return. Then the manual failover timedout.
Another possibility is that other primaries refuse to vote after receiving
the FAILOVER_AUTH_REQUEST, since in their's views, sender is still a primary,
so it refuse to vote, and then manual failover timedout.
```
void clusterSendFailoverAuthIfNeeded(clusterNode *node, clusterMsg *request) {
...
if (clusterNodeIsPrimary(node)) {
serverLog(LL_WARNING, "Failover auth denied to...
```
The reason is that, currently, we only update the node->replicaof information
when we receive a PING/PONG from the sender. For details, see clusterProcessPacket.
Therefore, in some scenarios, such as clusters with many nodes and a large
cluster-ping-interval (that is, cluster-node-timeout), the role change of the node
will be very delayed.
Added a DEBUG DISABLE-CLUSTER-RANDOM-PING command, send cluster ping
to a random node every second (see clusterCron).
Signed-off-by: Binbin <binloveplay1314@qq.com>
This limit should not restrict manual failover, otherwise in some
scenarios, manual failover will time out.
For example, if some FAILOVER_AUTH_REQUESTs or some FAILOVER_AUTH_ACKs
are lost during a manual failover, it cannot vote in the second manual
failover. Or in a mixed scenario of plain failover and manual failover,
it cannot vote for the subsequent manual failover.
The problem with the manual failover retry is that the mf will pause
the client 5s in the primary side. So every retry every manual failover
timed out is a bad move.
---------
Signed-off-by: Binbin <binloveplay1314@qq.com>
Co-authored-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
This commit hopefully improves the formatting of the codebase by setting
ColumnLimit to 0 and hence stopping clang-format from trying to put as
much stuff in one line as possible.
This change enabled us to remove most of `clang-format off` directives
and fixed a bunch of lines that looked like this:
```c
#define KEY \
VALUE /* comment */
```
Additionally, one pair of `clang-format off` / `clang-format on` had
`clang-format off` as the second comment and hence didn't enable the
formatting for the rest of the file. This commit addresses this issue as
well.
Please tell me if anything in the changes seem off. If everything is
fine, I will add this commit to `.git-blame-ignore-revs` later.
---------
Signed-off-by: Mikhail Koviazin <mikhail.koviazin@aiven.io>
This PR adjusts the logging conditions of clusterLogCantFailover
in this two ways.
1. For the same cant_failover_reason, we will print the log once
in CLUSTER_CANT_FAILOVER_RELOG_PERIOD, but its value is 10s, which
is a bit long, shorten it to 1s, so we can better track its state.
We get to see the system making progress by watching the message.
Using 1s also covers pretty much all cases as i don't see a reason
for using a <1s node timeout, test or prod.
2. We will not print logs before the nolog_fail_time, its value
is cluster-node-timeout+5000. This may casue us to lose some logs,
for example, if cluster-node-timeout is small, auth_timeout will
be 2000, and auth_retry_time will be 4000. In this case, we will
lose all the reasons during the election if the failover is timedout.
So remove the nolog_fail_time logic, since we still do have the
CLUSTER_CANT_FAILOVER_RELOG_PERIOD logic, we won't print too many
logs.
Signed-off-by: Binbin <binloveplay1314@qq.com>
Adds two new metrics for per-slot statistics, network-bytes-in and
network-bytes-out. The network bytes are inclusive of replication bytes
but exclude other types of network traffic such as clusterbus traffic.
#### network-bytes-in
The metric tracks network ingress bytes under per-slot context, by
reverse calculation of `c->argv_len_sum` and `c->argc`, stored under a
newly introduced field `c->net_input_bytes_curr_cmd`.
#### network-bytes-out
The metric tracks network egress bytes under per-slot context, by
hooking onto COB buffer mutations.
#### sample response
Both metrics are reported under the `CLUSTER SLOT-STATS` command.
```
127.0.0.1:6379> cluster slot-stats slotsrange 0 0
1) 1) (integer) 0
2) 1) "key-count"
2) (integer) 0
3) "cpu-usec"
4) (integer) 0
5) "network-bytes-in"
6) (integer) 0
7) "network-bytes-out"
8) (integer) 0
```
---------
Signed-off-by: Kyle Kim <kimkyle@amazon.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
Adds light-weight cluster bus header for pubsub message. Closes#557.
This also supports sending to and receiving non-light messages from
older versions of the engine.
The light-weight cluster bus message supports multiple pubsub messages
(payloads) for one pubsub channel. Receiving messages with multiple
payloads is supported but we're not yet sending such multi-payload
messages to other nodes.
---------
Signed-off-by: Roshan Khatri <rvkhatri@amazon.com>
The metric tracks cpu time in micro-seconds, sharing the same value as
`INFO COMMANDSTATS`, aggregated under per-slot context.
---------
Signed-off-by: Kyle Kim <kimkyle@amazon.com>
Signed-off-by: Madelyn Olson <madelyneolson@gmail.com>
Co-authored-by: Madelyn Olson <madelyneolson@gmail.com>
New configs:
* `cluster-announce-client-ipv4`
* `cluster-announce-client-ipv6`
New module API function:
* `ValkeyModule_GetClusterNodeInfoForClient`, takes a client id and is
otherwise just like its non-ForClient cousin.
If configured, one of these IP addresses are reported to each client in
CLUSTER SLOTS, CLUSTER SHARDS, CLUSTER NODES and redirects, replacing
the IP (`custer-announce-ip` or the auto-detected IP) of each node.
Which one is reported to the client depends on whether the client is
connected over IPv4 or IPv6.
Benefits:
* This allows clients using IPv4 to get the IPv4 addresses of all
cluster nodes and IPv6 clients to get the IPv6 clients.
* This allows the IPs visible to clients to be different to the IPs used
between the cluster nodes due to NAT'ing.
The information is propagated in the cluster bus using new Ping
extensions. (Old nodes without this feature ignore unknown Ping
extensions.)
This adds another dimension to CLUSTER SLOTS reply. It now depends on
the client's use of TLS, the IP address family and RESP version.
Refactoring: The cached connection type definition is moved from
connection.h (it actually has nothing to do with the connection
abstraction) to server.h and is changed to a bitmap, with one bit for
each of TLS, IPv6 and RESP3.
Fixes#337
---------
Signed-off-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
While debugging a cluster bus issue, found the cluster node flags were
represented in numbers. I generally find it easy when these are
represented as bitwise shift operation. It improves readability a bit.
Signed-off-by: Harkrishn Patro <harkrisp@amazon.com>
I have validated that these settings closely match the existing coding
style with one major exception on `BreakBeforeBraces`, which will be
`Attach` going forward. The mixed `BreakBeforeBraces` styles in the
current codebase are hard to imitate and also very odd IMHO - see below
```
if (a == 1) { /*Attach */
}
```
```
if (a == 1 ||
b == 2)
{ /* Why? */
}
```
Please do NOT merge just yet. Will add the github action next once the
style is reviewed/approved.
---------
Signed-off-by: Ping Xie <pingxie@google.com>
This commit adds a logic to cache `CLUSTER SLOTS` response for reduced
latency and also updates the cache when a change in the cluster is
detected.
Historically, `CLUSTER SLOTS` command was deprecated, however all the
server clients have been using `CLUSTER SLOTS` and have not migrated to
`CLUSTER SHARDS`. In future this logic can be added to any other
commands to improve the performance of the engine.
---------
Signed-off-by: Roshan Khatri <rvkhatri@amazon.com>
The "count" field of clusterMsg is only used for gossip.
Signed-off-by: Ben Totten <btotten@amazon.com>
Co-authored-by: Ben Totten <btotten@amazon.com>
Update comment suggesting clusterMsgPingExtTypes to clusterMsgPingtypes
as clusterMsgPingExtTypes does not exist
Signed-off-by: Ben Totten <btotten@amazon.com>
This includes comments used for module API documentation.
* Strategy for replacement: Regex search: `(//|/\*| \*|#).* ("|\()?(r|R)edis( |\.
|'|\n|,|-|\)|")(?!nor the names of its contributors)(?!Ltd.)(?!Labs)(?!Contributors.)`
* Don't edit copyright comments
* Replace "Redis version X.X" -> "Redis OSS version X.X" to distinguish
from newly licensed repository
* Replace "Redis Object" -> "Object"
* Exclude markdown for now
* Don't edit Lua scripting comments referring to redis.X API
* Replace "Redis Protocol" -> "RESP"
* Replace redis-benchmark, -cli, -server, -check-aof/rdb with "valkey-"
prefix
* Most other places, I use best judgement to either remove "Redis", or
replace with "the server" or "server"
Fixes#148
---------
Signed-off-by: Jacob Murphy <jkmurphy@google.com>
Signed-off-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
Ref: https://github.com/redis/redis/pull/12760
### Description
#### Fixes compatibilty of PlaceholderKV cluster (7.2 - extensions
enabled by default) with older Redis cluster (< 7.0 - extensions not
handled) .
With some of the extensions enabled by default in 7.2 version, new nodes
running 7.2 and above start sending out larger clusterbus message
payload including the ping extensions. This caused an incompatibility
with node running engine versions < 7.0. Old nodes (< 7.0) would receive
the payload from new nodes (> 7.2) would observe a payload length
(totlen) > (estlen) and would perform an early exit and won't process
the message.
This fix introduces a flag `extensions_supported` on the clusterMsg
indicating the sender node can handle extensions parsing. Once, a
receiver nodes receives a message with this flag set to 1, it would
update clusterNode new field extensions_supported and start sending out
extensions if it has any.
This PR also introduces a DEBUG sub command to enable/disable cluster
message extensions `process-clustermsg-extensions` feature.
Note: A successful `PING`/`PONG` is required as a sender for a given
node to be marked as `extensions_supported` and then extensions message
will be sent to it. This could cause a slight delay in receiving the
extensions message(s).
### Testing
TCL test verifying the cluster state is healthy irrespective of
enabling/disabling cluster message extensions feature.
---------
Signed-off-by: Harkrishn Patro <harkrisp@amazon.com>
We have achieved replacing `slots_to_keys` radix tree with key->slot
linked list (#9356), and then replacing the list with slot specific
dictionaries for keys (#11695).
Shard channels behave just like keys in many ways, and we also need a
slots->channels mapping. Currently this is still done by using a radix
tree. So we should split `server.pubsubshard_channels` into 16384 dicts
and drop the radix tree, just like what we did to DBs.
Some benefits (basically the benefits of what we've done to DBs):
1. Optimize counting channels in a slot. This is currently used only in
removing channels in a slot. But this is potentially more useful:
sometimes we need to know how many channels there are in a specific slot
when doing slot migration. Counting is now implemented by traversing the
radix tree, and with this PR it will be as simple as calling `dictSize`,
from O(n) to O(1).
2. The radix tree in the cluster has been removed. The shard channel
names no longer require additional storage, which can save memory.
3. Potentially useful in slot migration, as shard channels are logically
split by slots, thus making it easier to migrate, remove or add as a
whole.
4. Avoid rehashing a big dict when there is a large number of channels.
Drawbacks:
1. Takes more memory than using radix tree when there are relatively few
shard channels.
What this PR does:
1. in cluster mode, split `server.pubsubshard_channels` into 16384
dicts, in standalone mode, still use only one dict.
2. drop the `slots_to_channels` radix tree.
3. to save memory (to solve the drawback above), all 16384 dicts are
created lazily, which means only when a channel is about to be inserted
to the dict will the dict be initialized, and when all channels are
deleted, the dict would delete itself.
5. use `server.shard_channel_count` to keep track of the number of all
shard channels.
---------
Co-authored-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
More declerations can be moved into cluster_legacy.h
as they are not requied for the cluster api. The code
was simply moved, not changed in any way.
Signed-off-by: Josh Hershberg <yehoshua@redis.com>
Move clusterNode into cluster_legacy.h.
In order to achieve this some accessor methods
were added and also a refactor of how debugCommand
handles cluster related subcommands.
Signed-off-by: Josh Hershberg <yehoshua@redis.com>
Move clusterState into cluster_legacy.h. In order to achieve
this some "accessor" methods needed to be added to the
cluster API and some other minor refactors.
Signed-off-by: Josh Hershberg <yehoshua@redis.com>
Move some declerations from cluster.h to cluster_legacy.h.
The items moved are specific to the legacy clustering
implementation and DO NOT require any other refactoring
other than moving them from one file to another.
Signed-off-by: Josh Hershberg <yehoshua@redis.com>
