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MinIO Server Config Guide Docker Pulls

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Configuration Directory

Till MinIO release RELEASE.2018-08-02T23-11-36Z, MinIO server configuration file (config.json) was stored in the configuration directory specified by --config-dir or defaulted to ${HOME}/.minio. However from releases after RELEASE.2018-08-18T03-49-57Z, the configuration file (only), has been migrated to the storage backend (storage backend is the directory passed to MinIO server while starting the server). You can specify the location of your existing config using --config-dir, MinIO will migrate the config.json to your backend storage. Your current config.json will be renamed upon successful migration as config.json.deprecated in your current --config-dir. All your existing configurations are honored after this migration. Additionally --config-dir is now a legacy option which will is scheduled for removal in future, so please update your local startup, ansible scripts accordingly. 
minio server /data
MinIO also encrypts all the config, IAM and policies content with admin credentials.

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Certificate Directory

TLS certificates by default are stored under ${HOME}/.minio/certs directory. You need to place certificates here to enable HTTPS based access. Read more about How to secure access to MinIO server with TLS. Following is the directory structure for MinIO server with TLS certificates. 
$ mc tree --files ~/.minio
/home/user1/.minio
└─ certs
   ├─ CAs
   ├─ private.key
   └─ public.crt
You can provide a custom certs directory using --certs-dir command line option.

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Credentials

On MinIO admin credentials or root credentials are only allowed to be changed using ENVs namely MINIO_ROOT_USER and MINIO_ROOT_PASSWORD. Using the combination of these two values MinIO encrypts the config stored at the backend. 
export MINIO_ROOT_USER=minio
export MINIO_ROOT_PASSWORD=minio13
minio server /data
Rotating encryption with new credentials
Additionally if you wish to change the admin credentials, then MinIO will automatically detect this and re-encrypt with new credentials as shown below. For one time only special ENVs as shown below needs to be set for rotating the encryption config.
Old ENVs are never remembered in memory and are destroyed right after they are used to migrate your existing content with new credentials. You are safe to remove them after the server as successfully started, by restarting the services once again. 
export MINIO_ROOT_USER=newminio
export MINIO_ROOT_PASSWORD=newminio123
export MINIO_ROOT_USER_OLD=minio
export MINIO_ROOT_PASSWORD_OLD=minio123
minio server /data
Once the migration is complete, server will automatically unset the MINIO_ROOT_USER_OLD and MINIO_ROOT_PASSWORD_OLD with in the process namespace.
NOTE: Make sure to remove MINIO_ROOT_USER_OLD and MINIO_ROOT_PASSWORD_OLD in scripts or service files before next service restarts of the server to avoid double encryption of your existing contents.

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Region

KEY:
region  label the location of the server

ARGS:
name     (string)    name of the location of the server e.g. "us-west-rack2"
comment  (sentence)  optionally add a comment to this setting
or environment variables 
KEY:
region  label the location of the server

ARGS:
MINIO_REGION_NAME     (string)    name of the location of the server e.g. "us-west-rack2"
MINIO_REGION_COMMENT  (sentence)  optionally add a comment to this setting
Example: 
export MINIO_REGION_NAME="my_region"
minio server /data

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Storage Class

By default, parity for objects with standard storage class is set to N/2, and parity for objects with reduced redundancy storage class objects is set to 2. Read more about storage class support in MinIO server here. 
KEY:
storage_class  define object level redundancy

ARGS:
standard  (string)    set the parity count for default standard storage class e.g. "EC:4"
rrs       (string)    set the parity count for reduced redundancy storage class e.g. "EC:2"
comment   (sentence)  optionally add a comment to this setting
or environment variables 
KEY:
storage_class  define object level redundancy

ARGS:
MINIO_STORAGE_CLASS_STANDARD  (string)    set the parity count for default standard storage class e.g. "EC:4"
MINIO_STORAGE_CLASS_RRS       (string)    set the parity count for reduced redundancy storage class e.g. "EC:2"
MINIO_STORAGE_CLASS_COMMENT   (sentence)  optionally add a comment to this setting

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Cache

MinIO provides caching storage tier for primarily gateway deployments, allowing you to cache content for faster reads, cost savings on repeated downloads from the cloud. 
KEY:
cache  add caching storage tier

ARGS:
drives*  (csv)       comma separated mountpoints e.g. "/optane1,/optane2"
expiry   (number)    cache expiry duration in days e.g. "90"
quota    (number)    limit cache drive usage in percentage e.g. "90"
exclude  (csv)       comma separated wildcard exclusion patterns e.g. "bucket/*.tmp,*.exe"
after    (number)    minimum number of access before caching an object
comment  (sentence)  optionally add a comment to this setting
or environment variables 
KEY:
cache  add caching storage tier

ARGS:
MINIO_CACHE_DRIVES*  (csv)       comma separated mountpoints e.g. "/optane1,/optane2"
MINIO_CACHE_EXPIRY   (number)    cache expiry duration in days e.g. "90"
MINIO_CACHE_QUOTA    (number)    limit cache drive usage in percentage e.g. "90"
MINIO_CACHE_EXCLUDE  (csv)       comma separated wildcard exclusion patterns e.g. "bucket/*.tmp,*.exe"
MINIO_CACHE_AFTER    (number)    minimum number of access before caching an object
MINIO_CACHE_COMMENT  (sentence)  optionally add a comment to this setting

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Etcd

MinIO supports storing encrypted IAM assets and bucket DNS records on etcd.
NOTE: if path_prefix is set then MinIO will not federate your buckets, namespaced IAM assets are assumed as isolated tenants, only buckets are considered globally unique but performing a lookup with a bucket which belongs to a different tenant will fail unlike federated setups where MinIO would port-forward and route the request to relevant cluster accordingly. This is a special feature, federated deployments should not need to set path_prefix. 
KEY:
etcd  federate multiple clusters for IAM and Bucket DNS

ARGS:
endpoints*       (csv)       comma separated list of etcd endpoints e.g. "http://localhost:2379"
path_prefix      (path)      namespace prefix to isolate tenants e.g. "customer1/"
coredns_path     (path)      shared bucket DNS records, default is "/skydns"
client_cert      (path)      client cert for mTLS authentication
client_cert_key  (path)      client cert key for mTLS authentication
comment          (sentence)  optionally add a comment to this setting
or environment variables 
KEY:
etcd  federate multiple clusters for IAM and Bucket DNS

ARGS:
MINIO_ETCD_ENDPOINTS*       (csv)       comma separated list of etcd endpoints e.g. "http://localhost:2379"
MINIO_ETCD_PATH_PREFIX      (path)      namespace prefix to isolate tenants e.g. "customer1/"
MINIO_ETCD_COREDNS_PATH     (path)      shared bucket DNS records, default is "/skydns"
MINIO_ETCD_CLIENT_CERT      (path)      client cert for mTLS authentication
MINIO_ETCD_CLIENT_CERT_KEY  (path)      client cert key for mTLS authentication
MINIO_ETCD_COMMENT          (sentence)  optionally add a comment to this setting

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API

By default, there is no limitation on the number of concurrent requests that a server/cluster processes at the same time. However, it is possible to impose such limitation using the API subsystem. Read more about throttling limitation in MinIO server here. 
KEY:
api  manage global HTTP API call specific features, such as throttling, authentication types, etc.

ARGS:
requests_max               (number)    set the maximum number of concurrent requests, e.g. "1600"
requests_deadline          (duration)  set the deadline for API requests waiting to be processed e.g. "1m"
cors_allow_origin          (csv)       set comma separated list of origins allowed for CORS requests e.g. "https://example1.com,https://example2.com"
remote_transport_deadline  (duration)  set the deadline for API requests on remote transports while proxying between federated instances e.g. "2h"
or environment variables 
MINIO_API_REQUESTS_MAX               (number)    set the maximum number of concurrent requests, e.g. "1600"
MINIO_API_REQUESTS_DEADLINE          (duration)  set the deadline for API requests waiting to be processed e.g. "1m"
MINIO_API_CORS_ALLOW_ORIGIN          (csv)       set comma separated list of origins allowed for CORS requests e.g. "https://example1.com,https://example2.com"
MINIO_API_REMOTE_TRANSPORT_DEADLINE  (duration)  set the deadline for API requests on remote transports while proxying between federated instances e.g. "2h"

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Notifications

Notification targets supported by MinIO are in the following list. To configure individual targets please refer to more detailed documentation here 
notify_webhook        publish bucket notifications to webhook endpoints
notify_amqp           publish bucket notifications to AMQP endpoints
notify_kafka          publish bucket notifications to Kafka endpoints
notify_mqtt           publish bucket notifications to MQTT endpoints
notify_nats           publish bucket notifications to NATS endpoints
notify_nsq            publish bucket notifications to NSQ endpoints
notify_mysql          publish bucket notifications to MySQL databases
notify_postgres       publish bucket notifications to Postgres databases
notify_elasticsearch  publish bucket notifications to Elasticsearch endpoints
notify_redis          publish bucket notifications to Redis datastores

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Accessing configuration

All configuration changes can be made using mc admin config get/set/reset/export/import commands.

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List all config keys available

~ mc admin config set myminio/

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Obtain help for each key

~ mc admin config set myminio/ <key>
e.g: mc admin config set myminio/ etcd returns available etcd config args 
~ mc admin config set play/ etcd
KEY:
etcd  federate multiple clusters for IAM and Bucket DNS

ARGS:
endpoints*       (csv)       comma separated list of etcd endpoints e.g. "http://localhost:2379"
path_prefix      (path)      namespace prefix to isolate tenants e.g. "customer1/"
coredns_path     (path)      shared bucket DNS records, default is "/skydns"
client_cert      (path)      client cert for mTLS authentication
client_cert_key  (path)      client cert key for mTLS authentication
comment          (sentence)  optionally add a comment to this setting
To get ENV equivalent for each config args use --env flag 
~ mc admin config set play/ etcd --env
KEY:
etcd  federate multiple clusters for IAM and Bucket DNS

ARGS:
MINIO_ETCD_ENDPOINTS*       (csv)       comma separated list of etcd endpoints e.g. "http://localhost:2379"
MINIO_ETCD_PATH_PREFIX      (path)      namespace prefix to isolate tenants e.g. "customer1/"
MINIO_ETCD_COREDNS_PATH     (path)      shared bucket DNS records, default is "/skydns"
MINIO_ETCD_CLIENT_CERT      (path)      client cert for mTLS authentication
MINIO_ETCD_CLIENT_CERT_KEY  (path)      client cert key for mTLS authentication
MINIO_ETCD_COMMENT          (sentence)  optionally add a comment to this setting
This behavior is consistent across all keys, each key self documents itself with valid examples.

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Dynamic systems without restarting server

The following sub-systems are dynamic i.e., configuration parameters for each sub-systems can be changed while the server is running without any restarts. 
api                   manage global HTTP API call specific features, such as throttling, authentication types, etc.
heal                  manage object healing frequency and bitrot verification checks
scanner               manage namespace scanning for usage calculation, lifecycle, healing and more
NOTE: if you set any of the following sub-system configuration using ENVs, dynamic behavior is not supported.

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Usage scanner

Data usage scanner is enabled by default. The following configuration settings allow for more staggered delay in terms of usage calculation. The scanner adapts to the system speed and completely pauses when the system is under load. It is possible to adjust the speed of the scanner and thereby the latency of updates being reflected. The delays between each operation of the scanner can be adjusted by the mc admin config set alias/ delay=15.0. By default the value is 10.0. This means the scanner will sleep 10x the time each operation takes. In most setups this will keep the scanner slow enough to not impact overall system performance. Setting the delay key to a lower value will make the scanner faster and setting it to 0 will make the scanner run at full speed (not recommended in production). Setting it to a higher value will make the scanner slower, consuming less resources with the trade off of not collecting metrics for operations like healing and disk usage as fast. 
~ mc admin config set alias/ scanner
KEY:
scanner  manage namespace scanning for usage calculation, lifecycle, healing and more

ARGS:
delay     (float)     scanner delay multiplier, defaults to '10.0'
max_wait  (duration)  maximum wait time between operations, defaults to '15s'
Example: Following setting will decrease the scanner speed by a factor of 3, reducing the system resource use, but increasing the latency of updates being reflected. 
~ mc admin config set alias/ scanner delay=30.0
Once set the scanner settings are automatically applied without the need for server restarts.
NOTE: Data usage scanner is not supported under Gateway deployments.

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Healing

Healing is enabled by default. The following configuration settings allow for more staggered delay in terms of healing. The healing system by default adapts to the system speed and pauses up to ‘1sec’ per object when the system has max_io number of concurrent requests. It is possible to adjust the max_delay and max_io values thereby increasing the healing speed. The delays between each operation of the healer can be adjusted by the mc admin config set alias/ max_delay=1s and maximum concurrent requests allowed before we start slowing things down can be configured with mc admin config set alias/ max_io=30 . By default the wait delay is 1sec beyond 10 concurrent operations. This means the healer will sleep 1 second at max for each heal operation if there are more than 10 concurrent client requests. In most setups this is sufficient to heal the content after drive replacements. Setting max_delay to a lower value and setting max_io to a higher value would make heal go faster. 
~ mc admin config set alias/ heal
KEY:
heal  manage object healing frequency and bitrot verification checks

ARGS:
bitrotscan  (on|off)    perform bitrot scan on disks when checking objects during scanner
max_sleep   (duration)  maximum sleep duration between objects to slow down heal operation. eg. 2s
max_io      (int)       maximum IO requests allowed between objects to slow down heal operation. eg. 3
Example: The following settings will increase the heal operation speed by allowing healing operation to run without delay up to 100 concurrent requests, and the maximum delay between each heal operation is set to 300ms. 
~ mc admin config set alias/ heal max_delay=300ms max_io=100
Once set the healer settings are automatically applied without the need for server restarts.
NOTE: Healing is not supported under Gateway deployments.

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Environment only settings (not in config)

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Browser

Enable or disable access to web UI. By default it is set to on. You may override this field with MINIO_BROWSER environment variable. Example: 
export MINIO_BROWSER=off
minio server /data

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Domain

By default, MinIO supports path-style requests that are of the format http://mydomain.com/bucket/object. MINIO_DOMAIN environment variable is used to enable virtual-host-style requests. If the request Host header matches with (.+).mydomain.com then the matched pattern $1 is used as bucket and the path is used as object. More information on path-style and virtual-host-style here Example: 
export MINIO_DOMAIN=mydomain.com
minio server /data
For advanced use cases MINIO_DOMAIN environment variable supports multiple-domains with comma separated values. 
export MINIO_DOMAIN=sub1.mydomain.com,sub2.mydomain.com
minio server /data

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