https://github.com/minio/console takes over the functionality for the
future object browser development
Signed-off-by: Harshavardhana <harsha@minio.io>
With this change, MinIO's ILM supports transitioning objects to a remote tier.
This change includes support for Azure Blob Storage, AWS S3 compatible object
storage incl. MinIO and Google Cloud Storage as remote tier storage backends.
Some new additions include:
- Admin APIs remote tier configuration management
- Simple journal to track remote objects to be 'collected'
This is used by object API handlers which 'mutate' object versions by
overwriting/replacing content (Put/CopyObject) or removing the version
itself (e.g DeleteObjectVersion).
- Rework of previous ILM transition to fit the new model
In the new model, a storage class (a.k.a remote tier) is defined by the
'remote' object storage type (one of s3, azure, GCS), bucket name and a
prefix.
* Fixed bugs, review comments, and more unit-tests
- Leverage inline small object feature
- Migrate legacy objects to the latest object format before transitioning
- Fix restore to particular version if specified
- Extend SharedDataDirCount to handle transitioned and restored objects
- Restore-object should accept version-id for version-suspended bucket (#12091)
- Check if remote tier creds have sufficient permissions
- Bonus minor fixes to existing error messages
Co-authored-by: Poorna Krishnamoorthy <poorna@minio.io>
Co-authored-by: Krishna Srinivas <krishna@minio.io>
Signed-off-by: Harshavardhana <harsha@minio.io>
When an error is reported it is ignored and zipping continues with the next object.
However, if there is an error it will write a response to `writeWebErrorResponse(w, err)`, but responses are still being built.
Fixes#12082
Bonus: Exclude common compressed image types.
This commit introduces a new package `pkg/kms`.
It contains basic types and functions to interact
with various KMS implementations.
This commit also moves KMS-related code from `cmd/crypto`
to `pkg/kms`. Now, it is possible to implement a KMS-based
config data encryption in the `pkg/config` package.
Ensure that we don't use potentially broken algorithms for critical functions, whether it be a runtime problem or implementation problem for a specific platform.
The local node name is heavily used in tracing, create a new global
variable to store it. Multiple goroutines can access it since it won't be
changed later.
most of the delete calls today spend time in
a blocking operation where multiple calls need
to be recursively sent to delete the objects,
instead we can use rename operation to atomically
move the objects from the namespace to `tmp/.trash`
we can schedule deletion of objects at this
location once in 15, 30mins and we can also add
wait times between each delete operation.
this allows us to make delete's faster as well
less chattier on the drives, each server runs locally
a groutine which would clean this up regularly.
DNSCache dialer is a global value initialized in
init(), whereas `go` keeps `var =` before `init()`
, also we don't need to keep proxy routers as
global entities - register the forwarder as
necessary to avoid crashes.
additionally also configure http2 healthcheck
values to quickly detect unstable connections
and let them timeout.
also use single transport for proxying requests
Due to botched upstream renames of project repositories
and incomplete migration to go.mod support, our current
dependency version of `go.mod` had bugs i.e it was
using commits from master branch which didn't have
the required fixes present in release-3.4 branches
which leads to some rare bugs
https://github.com/etcd-io/etcd/pull/11477 provides
a workaround for now and we should migrate to this.
release-3.5 eventually claims to fix all of this
properly until then we cannot use /v3 import right now
Go stdlib resolver doesn't support caching DNS
resolutions, since we compile with CGO disabled
we are more probe to DNS flooding for all network
calls to resolve for DNS from the DNS server.
Under various containerized environments such as
VMWare this becomes a problem because there are
no DNS caches available and we may end up overloading
the kube-dns resolver under concurrent I/O.
To circumvent this issue implement a DNSCache resolver
which resolves DNS and caches them for around 10secs
with every 3sec invalidation attempted.
This change tracks bandwidth for a bucket and object
- [x] Add Admin API
- [x] Add Peer API
- [x] Add BW throttling
- [x] Admin APIs to set replication limit
- [x] Admin APIs for fetch bandwidth
In almost all scenarios MinIO now is
mostly ready for all sub-systems
independently, safe-mode is not useful
anymore and do not serve its original
intended purpose.
allow server to be fully functional
even with config partially configured,
this is to cater for availability of actual
I/O v/s manually fixing the server.
In k8s like environments it will never make
sense to take pod into safe-mode state,
because there is no real access to perform
any remote operation on them.
- select lockers which are non-local and online to have
affinity towards remote servers for lock contention
- optimize lock retry interval to avoid sending too many
messages during lock contention, reduces average CPU
usage as well
- if bucket is not set, when deleteObject fails make sure
setPutObjHeaders() honors lifecycle only if bucket name
is set.
- fix top locks to list out always the oldest lockers always,
avoid getting bogged down into map's unordered nature.
This commit refactors the certificate management implementation
in the `certs` package such that multiple certificates can be
specified at the same time. Therefore, the following layout of
the `certs/` directory is expected:
```
certs/
│
├─ public.crt
├─ private.key
├─ CAs/ // CAs directory is ignored
│ │
│ ...
│
├─ example.com/
│ │
│ ├─ public.crt
│ └─ private.key
└─ foobar.org/
│
├─ public.crt
└─ private.key
...
```
However, directory names like `example.com` are just for human
readability/organization and don't have any meaning w.r.t whether
a particular certificate is served or not. This decision is made based
on the SNI sent by the client and the SAN of the certificate.
***
The `Manager` will pick a certificate based on the client trying
to establish a TLS connection. In particular, it looks at the client
hello (i.e. SNI) to determine which host the client tries to access.
If the manager can find a certificate that matches the SNI it
returns this certificate to the client.
However, the client may choose to not send an SNI or tries to access
a server directly via IP (`https://<ip>:<port>`). In this case, we
cannot use the SNI to determine which certificate to serve. However,
we also should not pick "the first" certificate that would be accepted
by the client (based on crypto. parameters - like a signature algorithm)
because it may be an internal certificate that contains internal hostnames.
We would disclose internal infrastructure details doing so.
Therefore, the `Manager` returns the "default" certificate when the
client does not specify an SNI. The default certificate the top-level
`public.crt` - i.e. `certs/public.crt`.
This approach has some consequences:
- It's the operator's responsibility to ensure that the top-level
`public.crt` does not disclose any information (i.e. hostnames)
that are not publicly visible. However, this was the case in the
past already.
- Any other `public.crt` - except for the top-level one - must not
contain any IP SAN. The reason for this restriction is that the
Manager cannot match a SNI to an IP b/c the SNI is the server host
name. The entire purpose of SNI is to indicate which host the client
tries to connect to when multiple hosts run on the same IP. So, a
client will not set the SNI to an IP.
If we would allow IP SANs in a lower-level `public.crt` a user would
expect that it is possible to connect to MinIO directly via IP address
and that the MinIO server would pick "the right" certificate. However,
the MinIO server cannot determine which certificate to serve, and
therefore always picks the "default" one. This may lead to all sorts
of confusing errors like:
"It works if I use `https:instance.minio.local` but not when I use
`https://10.0.2.1`.
These consequences/limitations should be pointed out / explained in our
docs in an appropriate way. However, the support for multiple
certificates should not have any impact on how deployment with a single
certificate function today.
Co-authored-by: Harshavardhana <harsha@minio.io>
newDynamicTimeout should be allocated once, in-case
of temporary locks in config and IAM we should
have allocated timeout once before the `for loop`
This PR doesn't fix any issue as such, but provides
enough dynamism for the timeout as per expectation.
It is possible in situations when server was deployed
in asymmetric configuration in the past such as
```
minio server ~/fs{1...4}/disk{1...5}
```
Results in setDriveCount of 10 in older releases
but with fairly recent releases we have moved to
having server affinity which means that a set drive
count ascertained from above config will be now '4'
While the object layer make sure that we honor
`format.json` the storageClass configuration however
was by mistake was using the global value obtained
by heuristics. Which leads to prematurely using
lower parity without being requested by the an
administrator.
This PR fixes this behavior.
Generalize replication target management so
that remote targets for a bucket can be
managed with ARNs. `mc admin bucket remote`
command will be used to manage targets.
with the merge of https://github.com/etcd-io/etcd/pull/11823
etcd v3.5.0 will now have a properly imported versioned path
this fixes our pending migration to newer repo
When manual healing is triggered, one node in a cluster will
become the authority to heal. mc regularly sends new requests
to fetch the status of the ongoing healing process, but a load
balancer could land the healing request to a node that is not
doing the healing request.
This PR will redirect a request to the node based on the node
index found described as part of the client token. A similar
technique is also used to proxy ListObjectsV2 requests
by encoding this information in continuation-token
Looking into full disk errors on zoned setup. We don't take the
5% space requirement into account when selecting a zone.
The interesting part is that even considering this we don't
know the size of the object the user wants to upload when
they do multipart uploads.
It seems quite defensive to always upload multiparts to
the zone where there is the most space since all load will
be directed to a part of the cluster.
In these cases we make sure it can at least hold a 1GiB file
and we disadvantage fuller zones more by subtracting the
expected size before weighing.
- Implement a new xl.json 2.0.0 format to support,
this moves the entire marshaling logic to POSIX
layer, top layer always consumes a common FileInfo
construct which simplifies the metadata reads.
- Implement list object versions
- Migrate to siphash from crchash for new deployments
for object placements.
Fixes#2111
Bonus fixes in quota enforcement to use the
new datastructure and use timedValue to cache
a value/reload automatically avoids one less
global variable.
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
```
this is a major overhaul by migrating off all
bucket metadata related configs into a single
object '.metadata.bin' this allows us for faster
bootups across 1000's of buckets and as well
as keeps the code simple enough for future
work and additions.
Additionally also fixes#9396, #9394
This PR is to ensure that we call the relevant object
layer APIs for necessary S3 API level functionalities
allowing gateway implementations to return proper
errors as NotImplemented{}
This allows for all our tests in mint to behave
appropriately and can be handled appropriately as
well.
We should allow quorum errors to be send upwards
such that caller can retry while reading bucket
encryption/policy configs when server is starting
up, this allows distributed setups to load the
configuration properly.
Current code didn't facilitate this and would have
never loaded the actual configs during rolling,
server restarts.
This PR allows setting a "hard" or "fifo" quota
restriction at the bucket level. Buckets that
have reached the FIFO quota configured, will
automatically be cleaned up in FIFO manner until
bucket usage drops to configured quota.
If a bucket is configured with a "hard" quota
ceiling, all further writes are disallowed.
this commit avoids lots of tiny allocations, repeated
channel creates which are performed when filtering
the incoming events, unescaping a key just for matching.
also remove deprecated code which is not needed
anymore, avoids unexpected data structure transformations
from the map to slice.
global WORM mode is a complex piece for which
the time has passed, with the advent of S3 compatible
object locking and retention implementation global
WORM is sort of deprecated, this has been mentioned
in our documentation for some time, now the time
has come for this to go.
Add two new configuration entries, api.requests-max and
api.requests-deadline which have the same role of
MINIO_API_REQUESTS_MAX and MINIO_API_REQUESTS_DEADLINE.
- pkg/bucket/encryption provides support for handling bucket
encryption configuration
- changes under cmd/ provide support for AES256 algorithm only
Co-Authored-By: Poorna <poornas@users.noreply.github.com>
Co-authored-by: Harshavardhana <harsha@minio.io>
This is to ensure that when we have multiple tenants
deployed all sharing the same etcd for global bucket
should avoid listing each others buckets, this leads
to information leak which should be avoided unless
etcd is not namespaced for IAM assets in which case
it can be assumed that its a federated setup.
Federated setup and namespaced IAM assets on etcd
is not supported since namespacing is only useful
when you wish to separate the tenants as isolated
instances of MinIO.
This PR allows a new type of behavior, primarily
driven by the usecase of m3(mkube) multi-tenant
deployments with global bucket support.
This ensures that we can update the
- .minio.sys is updated for accounting/data usage purposes
- .minio.sys is updated to indicate if backend is encrypted
or not.
Currently, we use the top-level prefix "config/"
for all our IAM assets, instead of to provide
tenant-level separation bring 'path_prefix'
to namespace the access properly.
Fixes#8567
level - this PR builds on #8120 which
added PutBucketObjectLockConfiguration and
GetBucketObjectLockConfiguration APIS
This PR implements PutObjectRetention,
GetObjectRetention API and enhances
PUT and GET API operations to display
governance metadata if permissions allow.
- Supports migrating only when the credential ENVs are set,
so any FS mode deployments which do not have ENVs set will
continue to remain as is.
- Credential ENVs can be rotated using MINIO_ACCESS_KEY_OLD
and MINIO_SECRET_KEY_OLD envs, in such scenarios it allowed
to rotate the encrypted content to a new admin key.
- 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
The new auto healing model selects one node always responsible
for auto-healing the whole cluster, erasure set by erasure set.
If that node dies, another node will be elected as a leading
operator to perform healing.
This code also adds a goroutine which checks each 10 minutes
if there are any new unformatted disks and performs its healing
in that case, only the erasure set which has the new disk will
be healed.
- adding oauth support to MinIO browser (#8400) by @kanagaraj
- supports multi-line get/set/del for all config fields
- add support for comments, allow toggle
- add extensive validation of config before saving
- support MinIO browser to support proper claims, using STS tokens
- env support for all config parameters, legacy envs are also
supported with all documentation now pointing to latest ENVs
- preserve accessKey/secretKey from FS mode setups
- add history support implements three APIs
- ClearHistory
- RestoreHistory
- ListHistory
- add help command support for each config parameters
- all the bug fixes after migration to KV, and other bug
fixes encountered during testing.
This change is related to larger config migration PR
change, this is a first stage change to move our
configs to `cmd/config/` - divided into its subsystems
This PR is based off @sinhaashish's PR for object lifecycle
management, which includes support only for,
- Expiration of object
- Filter using object prefix (_not_ object tags)
N B the code for actual expiration of objects will be included in a
subsequent PR.
- Background Heal routine receives heal requests from a channel, either to
heal format, buckets or objects
- Daily sweeper lists all objects in all buckets, these objects
don't necessarly have read quorum so they can be removed if
these objects are unhealable
- Heal daily ops receives objects from the daily sweeper
and send them to the heal routine.
Inconsistencies can arise after applying bucket policies in
gateway mode, since all gateway instances do not share a
common shared state. This is by design to keep gateway as
shared nothing architecture.
This PR fixes such inconsistencies by reloading policy
if any from the backend.
Fixes#7723
In distributed mode, use REST API to acquire and manage locks instead
of RPC.
RPC has been completely removed from MinIO source.
Since we are moving from RPC to REST, we cannot use rolling upgrades as the
nodes that have not yet been upgraded cannot talk to the ones that have
been upgraded.
We expect all minio processes on all nodes to be stopped and then the
upgrade process to be completed.
Also force http1.1 for inter-node communication
Deprecate the use of Admin Peers concept and migrate all peer
communication to Notification subsystem. This finally allows
for a common subsystem for all peer notification in case of
distributed server deployments.
This PR adds pass-through, single encryption at gateway and double
encryption support (gateway encryption with pass through of SSE
headers to backend).
If KMS is set up (either with Vault as KMS or using
MINIO_SSE_MASTER_KEY),gateway will automatically perform
single encryption. If MINIO_GATEWAY_SSE is set up in addition to
Vault KMS, double encryption is performed.When neither KMS nor
MINIO_GATEWAY_SSE is set, do a pass through to backend.
When double encryption is specified, MINIO_GATEWAY_SSE can be set to
"C" for SSE-C encryption at gateway and backend, "S3" for SSE-S3
encryption at gateway/backend or both to support more than one option.
Fixes#6323, #6696
This commit adds an auto-encryption feature which allows
the Minio operator to ensure that uploaded objects are
always encrypted.
This change adds the `autoEncryption` configuration option
as part of the KMS conifguration and the ENV. variable
`MINIO_SSE_AUTO_ENCRYPTION:{on,off}`.
It also updates the KMS documentation according to the
changes.
Fixes#6502
This refactors the vault configuration by moving the
vault-related environment variables to `environment.go`
(Other ENV should follow in the future to have a central
place for adding / handling ENV instead of magic constants
and handling across different files)
Further this commit adds master-key SSE-S3 support.
The operator can specify a SSE-S3 master key using
`MINIO_SSE_MASTER_KEY` which will be used as master key
to derive and encrypt per-object keys for SSE-S3
requests.
This commit is also a pre-condition for SSE-S3
auto-encyption support.
Fixes#6329
This refactor brings a change which allows
targets to be added in a cleaner way and also
audit is now moved out.
This PR also simplifies logger dependency for auditing
This PR introduces two new features
- AWS STS compatible STS API named AssumeRoleWithClientGrants
```
POST /?Action=AssumeRoleWithClientGrants&Token=<jwt>
```
This API endpoint returns temporary access credentials, access
tokens signature types supported by this API
- RSA keys
- ECDSA keys
Fetches the required public key from the JWKS endpoints, provides
them as rsa or ecdsa public keys.
- External policy engine support, in this case OPA policy engine
- Credentials are stored on disks
ReadFile RPC input argument has been changed in commit a8f5939452959d27674560c6b803daa9,
however, RPC doesn't detect such a change when it calls other nodes with older versions.
Hence, bumping RPC version.
Fixes#6458
Add support for sse-s3 encryption with vault as KMS.
Also refactoring code to make use of headers and functions defined in
crypto package and clean up duplicated code.
This PR is the first set of changes to move the config
to the backend, the changes use the existing `config.json`
allows it to be migrated such that we can save it in on
backend disks.
In future releases, we will slowly migrate out of the
current architecture.
Fixes#6182
ANSI colors do not work on dumb terminals, in situations
when minio is running as a service under systemd.
This PR ensures we turn off color in those situations.
With CoreDNS now supporting etcdv3 as the DNS backend, we
can update our federation target to etcdv3. Users will now be
able to use etcdv3 server as the federation backbone.
Minio will update bucket data to etcdv3 and CoreDNS can pick
that data up and serve it as bucket style DNS path.
This PR adds CopyObject support for objects residing in buckets
in different Minio instances (where Minio instances are part of
a federated setup).
Also, added support for multiple Minio domain IPs. This is required
for distributed deployments, where one deployment may have multiple
nodes, each with a different public IP.
Added support for new RPC support using HTTP POST. RPC's
arguments and reply are Gob encoded and sent as HTTP
request/response body.
This patch also removes Go RPC based implementation.
This commit fixes a DoS vulnerability in the
request authentication. The root cause is an 'unlimited'
read-into-RAM from the request body.
Since this read happens before the request authentication
is verified the vulnerability can be exploit without any
access privileges.
This commit limits the size of the request body to 3 MB.
This is about the same size as AWS. The limit seems to be
between 1.6 and 3.2 MB - depending on the AWS machine which
is handling the request.
- remove old bucket policy handling
- add new policy handling
- add new policy handling unit tests
This patch brings support to bucket policy to have more control not
limiting to anonymous. Bucket owner controls to allow/deny any rest
API.
For example server side encryption can be controlled by allowing
PUT/GET objects with encryptions including bucket owner.
This PR adds disk based edge caching support for minio server.
Cache settings can be configured in config.json to take list of disk drives,
cache expiry in days and file patterns to exclude from cache or via environment
variables MINIO_CACHE_DRIVES, MINIO_CACHE_EXCLUDE and MINIO_CACHE_EXPIRY
Design assumes that Atime support is enabled and the list of cache drives is
fixed.
- Objects are cached on both GET and PUT/POST operations.
- Expiry is used as hint to evict older entries from cache, or if 80% of cache
capacity is filled.
- When object storage backend is down, GET, LIST and HEAD operations fetch
object seamlessly from cache.
Current Limitations
- Bucket policies are not cached, so anonymous operations are not supported in
offline mode.
- Objects are distributed using deterministic hashing among list of cache
drives specified.If one or more drives go offline, or cache drive
configuration is altered - performance could degrade to linear lookup.
Fixes#4026
This is a trival fix to support server level WORM. The feature comes
with an environment variable `MINIO_WORM`.
Usage:
```
$ export MINIO_WORM=on
$ minio server endpoint
```
This PR implements an object layer which
combines input erasure sets of XL layers
into a unified namespace.
This object layer extends the existing
erasure coded implementation, it is assumed
in this design that providing > 16 disks is
a static configuration as well i.e if you started
the setup with 32 disks with 4 sets 8 disks per
pack then you would need to provide 4 sets always.
Some design details and restrictions:
- Objects are distributed using consistent ordering
to a unique erasure coded layer.
- Each pack has its own dsync so locks are synchronized
properly at pack (erasure layer).
- Each pack still has a maximum of 16 disks
requirement, you can start with multiple
such sets statically.
- Static sets set of disks and cannot be
changed, there is no elastic expansion allowed.
- Static sets set of disks and cannot be
changed, there is no elastic removal allowed.
- ListObjects() across sets can be noticeably
slower since List happens on all servers,
and is merged at this sets layer.
Fixes#5465Fixes#5464Fixes#5461Fixes#5460Fixes#5459Fixes#5458Fixes#5460Fixes#5488Fixes#5489Fixes#5497Fixes#5496
This PR brings semver capabilities in our RPC layer to
ensure that we can upgrade the servers in rolling fashion
while keeping I/O in progress. This is only a framework change
the functionality remains the same as such and we do not
have any special API changes for now. But in future when
we bring in API changes we will be able to upgrade servers
without a downtime.
Additional change in this PR is to not abort when serverVersions
mismatch in a distributed cluster, instead wait for the quorum
treat the situation as if the server is down. This allows
for administrator to properly upgrade all the servers in the cluster.
Fixes#5393
in-memory caching cannot be cleanly implemented
without the access to GC which Go doesn't naturally
provide. At times we have seen that object caching
is more of an hindrance rather than a boon for
our use cases.
Removing it completely from our implementation
related to #5160 and #5182
This fix removes logrus package dependency and refactors the console
logging as the only logging mechanism by removing file logging support.
It rearranges the log message format and adds stack trace information
whenever trace information is not available in the error structure.
It also adds `--json` flag support for server logging.
When minio server is started with `--json` flag, all log messages are
displayed in json format, with no start-up and informational log
messages.
Fixes#5265#5220#5197
Save http trace to a file instead of displaying it onto the console.
the environment variable MINIO_HTTP_TRACE will be a filepath instead
of a boolean.
This to handle the scenario where both json and http tracing are
turned on. In that case, both http trace and json output are displayed
on the screen making the json not parsable. Loging this trace onto
a file helps us avoid that scenario.
Fixes#5263
This adds configurable data and parity options on a per object
basis. To use variable parity
- Users can set environment variables to cofigure variable
parity
- Then add header x-amz-storage-class to putobject requests
with relevant storage class values
Fixes#4997
This PR allows 'minio update' to not only shows update banner
but also allows for in-place upgrades.
Updates are done safely by validating the downloaded
sha256 of the binary.
Fixes#4781
When MINIO_TRACE_DIR is provided, create a new log file and store all
HTTP requests + responses data, body are excluded to reduce memory
consumption. MINIO_HTTP_TRACE=1 enables logging. Use non mem
consuming http req/resp recorders, the maximum is about 32k per request.
This logs to STDOUT, body logging is disabled for PutObject PutObjectPart
GetObject.
Previously init multipart upload stores metadata of an object which is
used for complete multipart. This patch makes azure gateway to store
metadata information of init multipart object in azure in the name of
'minio.sys.tmp/multipart/v1/<UPLOAD-ID>/meta.json' and uses this
information on complete multipart.
The default timeout of 30secs is not enough for high latency
environments, change these values to use 15 minutes instead.
With 30secs I/O timeouts seem to be quite common, this leads
to pretty much most SDKs and clients reconnect. This in-turn
causes significant performance problems. On a low latency
interconnect this can be quite challenging to transfer large
amounts of data. Setting this value to 15minutes covers
pretty much all known cases.
This PR was tested with `wondershaper <NIC> 20000 20000` by
limiting the network bandwidth to 20Mbit/sec. Default timeout
caused a significant amount of I/O timeouts, leading to
constant retires from the client. This seems to be more common
with tools like rclone, restic which have high concurrency set
by default. Once the value was fixed to 15minutes i/o timeouts
stopped and client could steadily upload data to the server
even while saturating the network.
Fixes#4670
* Refactor HTTP server to address bugs
* Remove unnecessary goroutine to start multiple TCP listeners.
* HTTP server waits for shutdown to maximum of Server.ShutdownTimeout
than per serverShutdownPoll.
* Handles new connection errors properly.
* Handles read and write timeout properly.
* Handles error on start of HTTP server properly by exiting minio
process.
Fixes#4494#4476 & fixed review comments
