[lxc-devel] [PATCH] pass on reboot flag and delete old veth on reboot

[Serge Hallyn]

Quoting Wolfgang Bumiller (w.bumiller at proxmox.com):
> When using a fixed interface name the recreation of it after
> a reboot caused an EEXIST.
> -) The reboot flag is now kept till after lxc_spawn instead
> of just before lxc_start in order to know whether to delete
> the old interface.
> -) If the reboot flag is set within instantiate_veth and a
> fixed name is used, the interface is now deleted before
> being recreated.
> 
> Signed-off-by: Wolfgang Bumiller <w.bumiller at proxmox.com>
> ---
>  src/lxc/conf.c         | 6 ++++--
>  src/lxc/lxccontainer.c | 3 +--
>  src/lxc/start.c        | 2 ++
>  3 files changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/src/lxc/conf.c b/src/lxc/conf.c
> index 9870455..ed2ad66 100644
> --- a/src/lxc/conf.c
> +++ b/src/lxc/conf.c
> @@ -2613,9 +2613,11 @@ static int instantiate_veth(struct lxc_handler *handler, struct lxc_netdev *netd
>  	char veth2buf[IFNAMSIZ], *veth2;
>  	int err;
>  
> -	if (netdev->priv.veth_attr.pair)
> +	if (netdev->priv.veth_attr.pair) {
>  		veth1 = netdev->priv.veth_attr.pair;
> -	else {
> +		if (handler->conf->reboot)
> +			lxc_netdev_delete_by_name(veth1);
> +	} else {
>  		err = snprintf(veth1buf, sizeof(veth1buf), "vethXXXXXX");
>  		if (err >= sizeof(veth1buf)) { /* can't *really* happen, but... */
>  			ERROR("veth1 name too long");
> diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
> index 1c103e8..b483dd8 100644
> --- a/src/lxc/lxccontainer.c
> +++ b/src/lxc/lxccontainer.c
> @@ -760,9 +760,9 @@ static bool do_lxcapi_start(struct lxc_container *c, int useinit, char * const a
>  		pid_fp = NULL;
>  	}
>  
> -reboot:
>  	conf->reboot = 0;
>  
> +reboot:
>  	if (lxc_check_inherited(conf, daemonize, -1)) {
>  		ERROR("Inherited fds found");
>  		ret = 1;
> @@ -774,7 +774,6 @@ reboot:
>  
>  	if (conf->reboot) {
>  		INFO("container requested reboot");
> -		conf->reboot = 0;
>  		goto reboot;
>  	}
>  
> diff --git a/src/lxc/start.c b/src/lxc/start.c
> index 6eded61..2fc026e 100644
> --- a/src/lxc/start.c
> +++ b/src/lxc/start.c
> @@ -1173,6 +1173,8 @@ int __lxc_start(const char *name, struct lxc_conf *conf,
>  		goto out_detach_blockdev;
>  	}
>  

The only problem I see is that if any of the failure cases above this in
__lxc_start hit, we'll be in an infinite loop re-trying lxc_start.  So
each failure case should set handler->conf->reboot = 0.

> +	handler->conf->reboot = 0;
> +
>  	netnsfd = get_netns_fd(handler->pid);
>  
>  	err = lxc_poll(name, handler);
> -- 
> 2.1.4
> 
> 
> _______________________________________________
> lxc-devel mailing list
> lxc-devel at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-devel