Context timeout might race on each other when timeouts are lower
i.e when two lock attempts happened very quickly on the same resource
and the servers were yet trying to establish quorum.
This situation can lead to locks held which wouldn't be unlocked
and subsequent lock attempts would fail.
This would require a complete server restart. A potential of this
issue happening is when server is booting up and we are trying
to hold a 'transaction.lock' in quick bursts of timeout.
Readiness as no reasoning to be cluster scope
because that is not how the k8s networking works
for pods, all the pods to a deployment are not
sharing the network in a singleton. Instead they
are run as local scopes to themselves, with
readiness failures the pod is potentially taken
out of the network to be resolvable - this
affects the distributed setup in myriad of
different ways.
Instead readiness should behave like liveness
with local scope alone, and should be a dummy
implementation.
This PR all the startup times and overal k8s
startup time dramatically improves.
Added another handler called as `/minio/health/cluster`
to understand the cluster scope health.
This PR adds a new configuration parameter which allows readiness
check to respond within 10secs, this can be reduced to a lower value
if necessary using
```
mc admin config set api ready_deadline=5s
```
or
```
export MINIO_API_READY_DEADLINE=5s
```
Metrics used to have its own code to calculate offline disks.
StorageInfo() was avoided because it is an expensive operation
by sending calls to all nodes.
To make metrics & server info share the same code, a new
argument `local` is added to StorageInfo() so it will only
query local disks when needed.
Metrics now calls StorageInfo() as server info handler does
but with the local flag set to false.
Co-authored-by: Praveen raj Mani <praveen@minio.io>
Co-authored-by: Harshavardhana <harsha@minio.io>
instead perform a liveness check call to
verify if server is online and print relevant
errors.
Also introduce a StorageErr string error type
instead of errors.New() deprecate usage of
VerifyFileError, DeleteFileError for gob,
change in datastructure also requires bump in
storage REST version to v13.
Fixes#8811
- We should declare a cluster ready even if read quorum is achieved (atleast n/2 disks are online).
- Such that, all the zones should have enough read quorum. Thus making the cluster ready for reads.
This PR refactors object layer handling such
that upon failure in sub-system initialization
server reaches a stage of safe-mode operation
wherein only certain API operations are enabled
and available.
This allows for fixing many scenarios such as
- incorrect configuration in vault, etcd,
notification targets
- missing files, incomplete config migrations
unable to read encrypted content etc
- any other issues related to notification,
policies, lifecycle etc
This is to avoid making calls to backend and requiring
gateways to allow permissions for ListBuckets() operation
just for Liveness checks, we can avoid this and make
our liveness checks to be more performant.
- This PR allows config KVS to be validated properly
without being affected by ENV overrides, rejects
invalid values during set operation
- Expands unit tests and refactors the error handling
for notification targets, returns error instead of
ignoring targets for invalid KVS
- Does all the prep-work for implementing safe-mode
style operation for MinIO server, introduces a new
global variable to toggle safe mode based operations
NOTE: this PR itself doesn't provide safe mode operations
With this PR, liveness check responds with 200 OK with "server-not-
initialized" header while objectLayer gets initialized. The header
is removed as objectLayer is initialized. This is to allow
MinIO distributed cluster to get started when running on an
orchestration platforms like Docker Swarm.
This PR also updates sample Swarm yaml files to use correct values
for healthcheck fields.
Fixes#8140
Health checking programs very frequently use /minio/health/live
to check health, hence we can avoid doing StorageInfo() and
ListBuckets() for FS/Erasure backend.
It was expected that in gateway mode, we do not know
the backend types whereas in NAS gateway since its
an extension of FS mode (standalone) this leads to
an issue in LivenessCheckHandler() which would perpetually
return 503, this would affect all kubernetes, openshift
deployments of NAS gateway.
Healthcheck handler in current implementation was
performing ListBuckets() to check for liveness of Minio
service. ListBuckets() implementation on the other hand
doesn't do quorum based listing and if one of the disks
returned error, an I/O error it would be lead to kubernetes
taking the minio pod down prematurely even if the disk
is not local to that minio server.
The reason is ListBuckets() call cannot be trusted to
provide us the valid information that we need, Minio is a
clustered application which is designed to handle disk
failures. Error on one of the disks doesn't mean the pod
should become fully non-operational.
This PR attempts to fix this by only checking for alive
disks which are local to each setup and also by simply
performing a Stat() operation, if the Stat() returned
error on all disks local to a particular server then
we can let kubernetes safely take it down, until then
we should be operational.
This PR adds readiness and liveness endpoints to probe Minio server
instance health. Endpoints can only be accessed without authentication
and the paths are /minio/health/live and /minio/health/ready for
liveness and readiness respectively.
The new healthcheck liveness endpoint is used for Docker healthcheck
now.
Fixes#5357Fixes#5514
Harshavardhana