|
| 1 | +--- |
| 2 | +title: Docker key storage issues |
| 3 | +description: Learn how to solve Docker key storage issues inside Coder workspaces. |
| 4 | +--- |
| 5 | + |
| 6 | +When using Coder, you may encounter the following error: |
| 7 | + |
| 8 | +```console |
| 9 | +docker: Error response from daemon: OCI runtime create failed: |
| 10 | +container_linux.go:370: starting container process caused: |
| 11 | +process_linux.go:459: container init caused: join session keyring: |
| 12 | +create session key: disk quota exceeded: unknown. |
| 13 | +``` |
| 14 | + |
| 15 | +## Why this happens |
| 16 | + |
| 17 | +The kernel allocates a system key for each container created. When lots of |
| 18 | +developers are sharing the same instance, you may run into limits on the number |
| 19 | +and size of keys each user can have. |
| 20 | + |
| 21 | +## Resolution |
| 22 | + |
| 23 | +To fix this error, you can increase `maxkeys` and `maxbytes`. These are global |
| 24 | +settings that apply to *all* users sharing the same system. You can modify this |
| 25 | +by adding the following to the `sysctl` configuration file: |
| 26 | + |
| 27 | +```console |
| 28 | +sudo sysctl -w kernel.keys.maxkeys=20000 |
| 29 | +sudo sysctl -w kernel.keys.maxbytes=400000 |
| 30 | +``` |
| 31 | + |
| 32 | +Alternatively, you can use a DaemonSet with `kubectl apply` to make changes to |
| 33 | +`sysctl`: |
| 34 | + |
| 35 | +```yaml |
| 36 | +apiVersion: apps/v1 |
| 37 | +kind: DaemonSet |
| 38 | +metadata: |
| 39 | + name: increase-limits |
| 40 | + namespace: kube-system |
| 41 | + labels: |
| 42 | + app: increase-limits |
| 43 | + k8s-app: increase-limits |
| 44 | +spec: |
| 45 | + selector: |
| 46 | + matchLabels: |
| 47 | + k8s-app: increase-limits |
| 48 | + template: |
| 49 | + metadata: |
| 50 | + labels: |
| 51 | + name: increase-limits |
| 52 | + k8s-app: increase-limits |
| 53 | + annotations: |
| 54 | + seccomp.security.alpha.kubernetes.io/defaultProfileName: runtime/default |
| 55 | + apparmor.security.beta.kubernetes.io/defaultProfileName: runtime/default |
| 56 | + spec: |
| 57 | + nodeSelector: |
| 58 | + kubernetes.io/os: linux |
| 59 | + initContainers: |
| 60 | + - name: sysctl |
| 61 | + image: alpine:3 |
| 62 | + command: |
| 63 | + - sysctl |
| 64 | + - -w |
| 65 | + - kernel.keys.maxkeys=20000 |
| 66 | + - kernel.keys.maxbytes=400000 |
| 67 | + resources: |
| 68 | + requests: |
| 69 | + cpu: 10m |
| 70 | + memory: 1Mi |
| 71 | + limits: |
| 72 | + cpu: 100m |
| 73 | + memory: 5Mi |
| 74 | + securityContext: |
| 75 | + # We need to run as root in a privileged container to modify |
| 76 | + # /proc/sys on the host (for sysctl) |
| 77 | + runAsUser: 0 |
| 78 | + privileged: true |
| 79 | + readOnlyRootFilesystem: true |
| 80 | + capabilities: |
| 81 | + drop: |
| 82 | + - ALL |
| 83 | + containers: |
| 84 | + - name: pause |
| 85 | + image: k8s.gcr.io/pause:3.5 |
| 86 | + command: |
| 87 | + - /pause |
| 88 | + resources: |
| 89 | + requests: |
| 90 | + cpu: 10m |
| 91 | + memory: 1Mi |
| 92 | + limits: |
| 93 | + cpu: 100m |
| 94 | + memory: 5Mi |
| 95 | + securityContext: |
| 96 | + runAsNonRoot: true |
| 97 | + runAsUser: 65535 |
| 98 | + allowPrivilegeEscalation: false |
| 99 | + privileged: false |
| 100 | + readOnlyRootFilesystem: true |
| 101 | + capabilities: |
| 102 | + drop: |
| 103 | + - ALL |
| 104 | + terminationGracePeriodSeconds: 5 |
| 105 | +``` |
| 106 | +
|
| 107 | +At a later point, you can delete the DaemonSet by running: |
| 108 | +
|
| 109 | +```console |
| 110 | +$ kubectl delete --namespace=kube-system daemonset increase-limits |
| 111 | +daemonset.apps "increase-limits" deleted |
| 112 | +``` |
| 113 | + |
| 114 | +However, note that the setting will persist until the node restarts or another |
| 115 | +program sets the `kernel.keys.maxkeys` and `kernel.keys.maxkeys` settings. |
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