File Transfer Protocol (FTP/SFTP)
Starting with Operator 5.0.7 and MinIO Server RELEASE.2023-04-20T17-56-55Z, you can use the SSH File Transfer Protocol (SFTP) to interact with the objects on a MinIO Operator Tenant deployment.
SFTP is defined by the Internet Engineering Task Force (IETF) as an extension of SSH 2.0. It allows file transfer over SSH for use with Transport Layer Security (TLS) and virtual private network (VPN) applications.
Enabling SFTP does not affect other MinIO features.
Starting with MinIO Server RELEASE.2023-04-20T17-56-55Z, you can use the File Transfer Protocol (FTP) to interact with the objects on a MinIO deployment.
You must specifically enable FTP or SFTP when starting the server. Enabling either server type does not affect other MinIO features.
This page uses the abbreviation FTP throughout, but you can use any of the supported FTP protocols described below.
Supported Protocols
The MinIO Operator only supports configuring SSH File Transfer Protocol (SFTP).
When enabled, MinIO supports FTP access over the following protocols:
SSH File Transfer Protocol (SFTP)
SFTP is defined by the Internet Engineering Task Force (IETF) as an extension of SSH 2.0. SFTP allows file transfer over SSH for use with Transport Layer Security (TLS) and virtual private network (VPN) applications.
Your FTP client must support SFTP.
File Transfer Protocol over SSL/TLS (FTPS)
FTPS allows for encrypted FTP communication with TLS certificates over the standard FTP communication channel. FTPS should not be confused with SFTP, as FTPS does not communicate over a Secure Shell (SSH).
Your FTP client must support FTPS.
File Transfer Protocol (FTP)
Unencrypted file transfer.
MinIO does not recommend using unencrypted FTP for file transfer.
Supported Commands
When enabled, MinIO supports the following SFTP operations:
get
put
ls
mkdir
rmdir
delete
MinIO does not support either append
or rename
operations.
Considerations
Versioning
SFTP clients can only operate on the latest version of an object. Specifically:
For read operations, MinIO only returns the latest version of the requested object(s) to the SFTP client.
For write operations, MinIO applies normal versioning behavior and creates a new object version at the specified namespace.
rm
andrmdir
operations createDeleteMarker
objects.
Authentication and Access
SFTP access requires the same authentication as any other S3 client. MinIO supports the following authentication providers:
MinIO IDP users and their service accounts
Active Directory/LDAP users and their service accounts
OpenID/OIDC service accounts
STS credentials cannot access buckets or objects over SFTP.
Authenticated users can access buckets and objects based on the policies assigned to the user or parent user account.
The SFTP protocol does not require any of the admin:*
permissions.
You may not perform other MinIO admin actions with SFTP.
Prerequisites
MinIO Operator v5.0.7 or later.
Enable an SFTP port (8022) for the server.
A port to use for the SFTP commands and a range of ports to allow the SFTP server to request to use for the data transfer.
MinIO RELEASE.2023-04-20T17-56-55Z or later.
Enable an FTP or SFTP port for the server.
A port to use for the FTP commands and a range of ports to allow the FTP server to request to use for the data transfer.
Procedure
Enable SFTP for the desired Tenant:
Use the following Kubectl command to edit the Tenant YAML configuration:
kubectl edit tenants/my-tenant -n my-tenant-ns
Replace
my-tenant
andmy-tenant-ns
with the desired Tenant and namespace.In the
features:
section, set the value ofenableSFTP
totrue
:spec: configuration: name: my-tenant-env-configuration credsSecret: name: my-tenant-secret exposeServices: console: true minio: true features: enableSFTP: true
Kubectl restarts MinIO to apply the change.
You may also set
enableSFTP
in your Helm chart or Kustomize configuration to enable SFTP for newly created Tenants.If needed, configure ingress for the SFTP port according to your local policies.
Validate the configuration
The following
kubectl get
command uses yq to display the value ofenableSFTP
, indicating whether SFTP is enabled:kubectl get tenants/my-tenant -n my-tenant-ns -o yaml | yq '.spec.features'
Replace
my-tenant
andmy-tenant-ns
with the desired Tenant and namespace.If SFTP is enabled, the output resembles the following:
enableSFTP: true
Use your preferred SFTP client to connect to the MinIO deployment. You must connect as a user whose policies allow access to the desired buckets and objects.
The specifics of connecting to the MinIO deployment depend on your SFTP client. Refer to the documentation for your client.
The following example connects to the MinIO Tenant SFTP server forwarded to the local host system, and lists the contents of a bucket named
runner
.> sftp -P 8022 minio@localhost minio@localhost's password: Connected to localhost. sftp> ls runner/ chunkdocs testdir
The following kubectl get
command uses yq to display the value of enableSFTP
, indicating whether SFTP is enabled:
kubectl get tenants/my-tenant -n my-tenant-ns -o yaml | yq '.spec.features'
Replace my-tenant
and my-tenant-ns
with the desired Tenant and namespace.
If SFTP is enabled, the output resembles the following:
enableSFTP: true
Start MinIO with an FTP and/or SFTP port enabled.
The following example starts MinIO with FTPS enabled.
minio server http://server{1...4}/disk{1...4} \ --ftp="address=:8021" \ --ftp="passive-port-range=30000-40000" \ --ftp="tls-private-key=path/to/private.key" \ --ftp="tls-public-cert=path/to/public.crt" \ ...
Note
Omit
tls-private-key
andtls-public-cert
to use the MinIO default TLS keys for FTPS. For more information, see the TLS on MinIO documentation.minio server http://server{1...4}/disk{1...4} \ --ftp="address=:8021" \ --ftp="passive-port-range=30000-40000" \ --sftp="address=:8022" \ --sftp="ssh-private-key=/home/miniouser/.ssh/id_rsa" \ ...
See the
minio server --ftp
andminio server --sftp
for details on using these flags to start the MinIO service. To connect to the an FTP port with TLS (FTPS), pass thetls-private-key
andtls-public-cert
keys and values, as well, unless using the MinIO default TLS keys.The output of the command should return a response that resembles the following:
MinIO FTP Server listening on :8021 MinIO SFTP Server listening on :8022
Use your preferred FTP client to connect to the MinIO deployment. You must connect as a user whose policies allow access to the desired buckets and objects.
The specifics of connecting to the MinIO deployment depend on your FTP client. Refer to the documentation for your client.
To connect over TLS or through SSH, you must use a client that supports the desired protocol.
Connect to MinIO
The following example connects to an SFTP server, and lists the contents of a bucket named
runner
.> sftp -P 8022 minio@localhost minio@localhost's password: Connected to localhost. sftp> ls runner/ chunkdocs testdir
The following uses the Linux uses the FTP CLI client to connect to the MinIO server using
minio
credentials to list contents in a bucket namedrunner
> ftp localhost -P 8021 Connected to localhost. 220 Welcome to MinIO FTP Server Name (localhost:user): minio 331 User name ok, password required Password: 230 Password ok, continue Remote system type is UNIX. Using binary mode to transfer files. ftp> ls runner/ 229 Entering Extended Passive Mode (|||39155|) 150 Opening ASCII mode data connection for file list drwxrwxrwx 1 nobody nobody 0 Jan 1 00:00 chunkdocs/ drwxrwxrwx 1 nobody nobody 0 Jan 1 00:00 testdir/ ...
Download an Object
This example lists items in a bucket, then downloads the contents of the bucket.
> sftp -P 8022 minio@localhost minio@localhost's password: Connected to localhost. sftp> ls runner/ chunkdocs testdir sftp> get runner/chunkdocs/metadata metadata Fetching /runner/chunkdocs/metadata to metadata metadata 100% 226 16.6KB/s 00:00 sftp>
This example lists items in a bucket, then downloads the contents of the bucket.
> ftp localhost -P 8021 Connected to localhost. 220 Welcome to MinIO FTP Server Name (localhost:user): minio 331 User name ok, password required Password: 230 Password ok, continue Remote system type is UNIX. Using binary mode to transfer files.ftp> ls runner/chunkdocs/metadata 229 Entering Extended Passive Mode (|||44269|) 150 Opening ASCII mode data connection for file list -rwxrwxrwx 1 nobody nobody 45 Apr 1 06:13 chunkdocs/metadata 226 Closing data connection, sent 75 bytes ftp> get (remote-file) runner/chunkdocs/metadata (local-file) test local: test remote: runner/chunkdocs/metadata 229 Entering Extended Passive Mode (|||37785|) 150 Data transfer starting 45 bytes 45 3.58 KiB/s 226 Closing data connection, sent 45 bytes 45 bytes received in 00:00 (3.55 KiB/s) ...
Connect to MinIO Using SFTP with a Certificate Key File
New in version RELEASE.2024-05-07T06-41-25Z.
MinIO supports mutual TLS (mTLS) certificate-based authentication on SFTP, where both the server and the client verify the authenticity of each other.
This type of authentication requires the following:
Public key file for the trusted certificate authority
Public key file for the MinIO Server minted and signed by the trusted certificate authority
Public key file for the user minted and signed by the trusted certificate authority for the client connecting by SFTP and located in the user’s
.ssh
folder (or equivalent for the operating system)
The keys must include a principals list of the user(s) that can authenticate with the key:
ssh-keygen -s ~/.ssh/ca_user_key -I miniouser -n miniouser -V +1h -z 1 miniouser1.pub
-s
specifies the path to the certificate authority public key to use for generating this key. The specified public key must have aprincipals
list that includes this user.-I
specifies the key identity for the public key.-n
creates theuser principals
list for which this key is valid. You must include the user for which this key is valid, and the user must match the username in MinIO.-V
limits the duration for which the generated key is valid. In this example, the key is valid for one hour. Adjust the duration for your requirements.-z
adds a serial number to the key to distinguish this generated public key from other keys signed by the same certificate authority public key.
MinIO requires specifying the Certificate Authority used to sign the certificates for SFTP access.
Start or restart the MinIO Server and specify the path to the trusted certificate authority’s public key using an --sftp="trusted-user-ca-key=PATH"
flag:
minio server {path-to-server} --sftp="trusted-user-ca-key=/path/to/.ssh/ca_user_key.pub" {...other flags}
When connecting to the MinIO Server with SFTP, the client verifies the MinIO Server’s certificate. The client then passes its own certificate to the MinIO Server. The MinIO Server verifies the key created above by comparing its value to the the known public key from the certificate authority provided at server startup.
Once the MinIO Server verifies the client’s certificate, the user can connect to the MinIO server over SFTP:
sftp -P <SFTP port> <server IP>
Require service account or LDAP for authentication
To force authentication to SFTP using LDAP or service account credentials, append a suffix to the username.
Valid suffixes are either =ldap
or =svc
.
> sftp -P 8022 my-ldap-user=ldap@[minio@localhost]:/bucket
> sftp -P 8022 my-ldap-user=svc@[minio@localhost]:/bucket
Replace
my-ldap-user
with the username to use.Replace
[minio@localhost]
with the address of the MinIO server.