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virtcontainers: kata_agent: Rollback when createContainer fails

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In case the container creation fails, we need a proper rollback
regarding the mounts previously performed.

Fixes #135

Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
This commit is contained in:
Sebastien Boeuf 2018-03-30 14:16:04 -07:00
parent 788664809f
commit e98f9305ad
1 changed files with 27 additions and 7 deletions
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34
virtcontainers/kata_agent.go
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@ -599,7 +599,25 @@ func (k *kataAgent) appendDevices(deviceList []*grpc.Device, devices []Device) [
return deviceList
}
func (k *kataAgent) createContainer(pod *Pod, c *Container) (*Process, error) {
// rollbackFailingContainerCreation rolls back important steps that might have
// been performed before the container creation failed.
// - Unmount container volumes.
// - Unmount container rootfs.
func (k *kataAgent) rollbackFailingContainerCreation(c *Container, err error) {
if err != nil {
if c != nil {
if err2 := c.unmountHostMounts(); err2 != nil {
k.Logger().WithError(err2).Error("rollback failed unmountHostMounts()")
}
if err2 := bindUnmountContainerRootfs(kataHostSharedDir, c.pod.id, c.id); err2 != nil {
k.Logger().WithError(err2).Error("rollback failed bindUnmountContainerRootfs()")
}
}
}
}
func (k *kataAgent) createContainer(pod *Pod, c *Container) (p *Process, err error) {
ociSpecJSON, ok := c.config.Annotations[vcAnnotations.ConfigJSONKey]
if !ok {
return nil, errorMissingOCISpec
@ -619,6 +637,10 @@ func (k *kataAgent) createContainer(pod *Pod, c *Container) (*Process, error) {
rootPathParent := filepath.Join(kataGuestSharedDir, c.id)
rootPath := filepath.Join(rootPathParent, rootfsDir)
// In case the container creation fails, the following defer statement
// takes care of rolling back actions previously performed.
defer k.rollbackFailingContainerCreation(c, err)
if c.state.Fstype != "" {
// This is a block based device rootfs.
@ -667,27 +689,25 @@ func (k *kataAgent) createContainer(pod *Pod, c *Container) (*Process, error) {
// (kataGuestSharedDir) is already mounted in the
// guest. We only need to mount the rootfs from
// the host and it will show up in the guest.
if err := bindMountContainerRootfs(kataHostSharedDir, pod.id, c.id, c.rootFs, false); err != nil {
bindUnmountAllRootfs(kataHostSharedDir, *pod)
if err = bindMountContainerRootfs(kataHostSharedDir, pod.id, c.id, c.rootFs, false); err != nil {
return nil, err
}
}
ociSpec := &specs.Spec{}
if err := json.Unmarshal([]byte(ociSpecJSON), ociSpec); err != nil {
if err = json.Unmarshal([]byte(ociSpecJSON), ociSpec); err != nil {
return nil, err
}
// Handle container mounts
newMounts, err := c.mountSharedDirMounts(kataHostSharedDir, kataGuestSharedDir)
if err != nil {
bindUnmountAllRootfs(kataHostSharedDir, *pod)
return nil, err
}
// We replace all OCI mount sources that match our container mount
// with the right source path (The guest one).
if err := k.replaceOCIMountSource(ociSpec, newMounts); err != nil {
if err = k.replaceOCIMountSource(ociSpec, newMounts); err != nil {
return nil, err
}
@ -714,7 +734,7 @@ func (k *kataAgent) createContainer(pod *Pod, c *Container) (*Process, error) {
OCI: grpcSpec,
}
if _, err := k.sendReq(req); err != nil {
if _, err = k.sendReq(req); err != nil {
return nil, err
}