<![CDATA[SFTPGo fails to start: "could not start SFTP server: open id_rsa: read-only file system"]]>Hi,

SFTPGo 2.7.6 fails to start on my Cloudron instance because it cannot create its SSH host key. The app restarts in a loop and the healthcheck never passes.

Environment

  • Cloudron version: 10.0.5
  • SFTPGo package version: com.sftpgo.cloudronapp@1.4.5

Logs
No host keys configured and "id_rsa" does not exist; try to create a new host key
error creating host key "id_rsa": open id_rsa: read-only file system
could not start SFTP server: open id_rsa: read-only file system
Healthcheck error: AbortError: The operation was aborted

The log shows HostKeys:[] in the SFTP config and config dir: .. SFTPGo therefore tries to write id_rsa into its working directory, which is on the read-only filesystem (/app/code). The failure is retried every minute (restart loop).

Everything else initializes fine: PostgreSQL migration (schema v33), SMTP, OIDC, HTTP on 8080 and WebDAV on 8888.

Workaround
Setting the host keys explicitly to a writable location fixed it for me. In /app/data/sftpgo.json:

"sftpd": {
"bindings": [{"port": 2022}],
"host_keys": ["/app/data/id_rsa", "/app/data/id_ecdsa", "/app/data/id_ed25519"]
}

]]>https://forum.cloudron.io/topic/16053/sftpgo-fails-to-start-could-not-start-sftp-server-open-id_rsa-read-only-file-systemRSS for NodeMon, 19 Oct 2026 01:47:47 GMTFri, 02 Oct 2026 07:05:34 GMT60<![CDATA[Reply to SFTPGo fails to start: "could not start SFTP server: open id_rsa: read-only file system" on Fri, 02 Oct 2026 08:30:52 GMT]]>Hello @valexico

I have reproduced it and identified the cause.
An app update will be available soon that will fix starting the @sftpgo app without SFTPd initially configured.

]]>https://forum.cloudron.io/post/130352https://forum.cloudron.io/post/130352Fri, 02 Oct 2026 08:30:52 GMT<![CDATA[Reply to SFTPGo fails to start: "could not start SFTP server: open id_rsa: read-only file system" on Fri, 02 Oct 2026 08:25:45 GMT]]>Hello @valexico

I am trying to reproduce this and will report back.

]]>https://forum.cloudron.io/post/130351https://forum.cloudron.io/post/130351Fri, 02 Oct 2026 08:25:45 GMT<![CDATA[Reply to SFTPGo fails to start: "could not start SFTP server: open id_rsa: read-only file system" on Fri, 02 Oct 2026 08:21:42 GMT]]>I just install the app without SFTPd and then the app was not able to start with those logs
https://paste.cloudron.io/p/mole-panda-whale

then I did my workaround and restarted the app to boot properly

Workaround
"sftpd": {
"bindings": [{"port": 2022}],
"host_keys": ["/app/data/id_rsa", "/app/data/id_ecdsa", "/app/data/id_ed25519"]
}

]]>https://forum.cloudron.io/post/130350https://forum.cloudron.io/post/130350Fri, 02 Oct 2026 08:21:42 GMT<![CDATA[Reply to SFTPGo fails to start: "could not start SFTP server: open id_rsa: read-only file system" on Fri, 02 Oct 2026 08:17:26 GMT]]>Hello @valexico

When SFTPd is not enabled the host_key for SFTPd will not be configured.
So when you enable SFTPd and save, it will restart the app and configure the default host_key.

Please answer the following question:

You did install the app without SFTPd enabled.
Then you did what exactly to get to the state of:

@Valexico said:

No host keys configured and "id_rsa" does not exist; try to create a new host key
error creating host key "id_rsa": open id_rsa: read-only file system
could not start SFTP server: open id_rsa: read-only file system
Healthcheck error: AbortError: The operation was aborted

]]>https://forum.cloudron.io/post/130349https://forum.cloudron.io/post/130349Fri, 02 Oct 2026 08:17:26 GMT<![CDATA[Reply to SFTPGo fails to start: "could not start SFTP server: open id_rsa: read-only file system" on Fri, 02 Oct 2026 08:09:29 GMT]]>I did install it like this :

digi-studio 2026-10-02 at 10.08.47.jpeg

is this the cause ?

]]>https://forum.cloudron.io/post/130345https://forum.cloudron.io/post/130345Fri, 02 Oct 2026 08:09:29 GMT<![CDATA[Reply to SFTPGo fails to start: "could not start SFTP server: open id_rsa: read-only file system" on Fri, 02 Oct 2026 08:07:06 GMT]]>Hello @valexico
I could not reproduce this with a fresh @sftpgo installation.

@Valexico said:

No host keys configured

By default, the @sftpgo app always generates the /app/data/sftpgo_host_key and automatically configures the /app/data/sftpgo.json file.
Only when the app is started without the SFTPd port the config file does not automatically configure the '.sftpd.host_keys[0]' config entry:
When enabling the SFTPd port it configures it again.
Just tested this.

Could please share the real log file from your @sftpgo app via https://paste.cloudron.io/ ?

]]>https://forum.cloudron.io/post/130342https://forum.cloudron.io/post/130342Fri, 02 Oct 2026 08:07:06 GMT<![CDATA[Reply to SFTPGo fails to start: "could not start SFTP server: open id_rsa: read-only file system" on Fri, 02 Oct 2026 07:41:43 GMT]]>Hello @valexico
Thanks for reporting, I will look into this.

]]>https://forum.cloudron.io/post/130341https://forum.cloudron.io/post/130341Fri, 02 Oct 2026 07:41:43 GMT