improve error message when dbus-user-session is not installed

Before:

```console
$ docker --context=rootless run -it --rm alpine
docker: Error response from daemon: OCI runtime create failed: unable to start
container process: unable to apply cgroup configuration: unable to start unit
"docker-7ef2c29ccafc1ed9c7fd9859337e5b79870d8ccb282f560e43060a847a6c5310.scope"
(properties [{Name:Description Value:"libcontainer container
7ef2c29ccafc1ed9c7fd9859337e5b79870d8ccb282f560e43060a847a6c5310"} {Name:Slice
Value:"user.slice"} {Name:PIDs Value:@au [6286]} {Name:Delegate Value:true}
{Name:MemoryAccounting Value:true} {Name:CPUAccounting Value:true}
{Name:IOAccounting Value:true} {Name:TasksAccounting Value:true}
{Name:DefaultDependencies Value:false}]): read unix @->/run/systemd/private:
read: connection reset by peer: unknown.
```

After:

```console
$ docker --context=rootless run -it --rm alpine
docker: Error response from daemon: OCI runtime create failed: unable to start
container process: unable to apply cgroup configuration: unable to start unit
"docker-8527d83e046da46d1b56b1c6a89324e687da1c365e044b8dde52cfbf1c461c5a.scope"
(properties [{Name:Description Value:"libcontainer container
8527d83e046da46d1b56b1c6a89324e687da1c365e044b8dde52cfbf1c461c5a"} {Name:Slice
Value:"user.slice"} {Name:PIDs Value:@au [10012]} {Name:Delegate Value:true}
{Name:MemoryAccounting Value:true} {Name:CPUAccounting Value:true}
{Name:IOAccounting Value:true} {Name:TasksAccounting Value:true}
{Name:DefaultDependencies Value:false}]): failed to connect to dbus (hint: for
rootless containers, maybe you need to install dbus-user-session package, see
https://github.com/opencontainers/runc/blob/master/docs/cgroup-v2.md): read
unix @->/run/systemd/private: read: connection reset by peer: unknown.
```

For moby/moby issue 42793

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
(cherry picked from commit 1f5798f784)
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
This commit is contained in:
Akihiro Suda
2021-08-27 17:00:09 +09:00
parent 04bcb7c715
commit cbb5ef5c6a
+5 -1
View File
@@ -4,6 +4,7 @@ package systemd
import (
"context"
"fmt"
"sync"
systemdDbus "github.com/coreos/go-systemd/v22/dbus"
@@ -54,7 +55,10 @@ func (d *dbusConnManager) getConnection() (*systemdDbus.Conn, error) {
conn, err := d.newConnection()
if err != nil {
return nil, err
// When dbus-user-session is not installed, we can't detect whether we should try to connect to user dbus or system dbus, so d.dbusRootless is set to false.
// This may fail with a cryptic error "read unix @->/run/systemd/private: read: connection reset by peer: unknown."
// https://github.com/moby/moby/issues/42793
return nil, fmt.Errorf("failed to connect to dbus (hint: for rootless containers, maybe you need to install dbus-user-session package, see https://github.com/opencontainers/runc/blob/master/docs/cgroup-v2.md): %w", err)
}
dbusC = conn
return conn, nil