[lxc-devel] [PATCH 2/2] introduce lxc-snapshot
Stéphane Graber
stgraber at ubuntu.com
Tue Sep 10 16:31:57 UTC 2013
On Fri, Sep 06, 2013 at 06:11:05PM -0500, Serge Hallyn wrote:
> Hopefully someone else will come in and spruce it up :) This
> version is as simple as can be
>
> lxc-snapshot -n a1
> create a snapshot of a1
> echo "second commit" > /tmp/a
> lxc-snapshot -n a1 -c /tmp/a
> create a snapshot of a1 with /tmp/a as a commit comment
> lxc-snapshot -n a1 -L
> list a1's snapshots
> lxc-snapshot -n a1 -L -C
> list a1's snapshots along with commit comments
> lxc-snapshot -n a1 -r snap0 a2
> restore snapshot 0 of a1 as container a2
>
> Some easy nice-to-haves:
>
> 1. sort snapshots in the list
> 2. allow a comment to be given in-line
> 3. an option to remove a snapshot?
>
> Removing a snapshot can just as well be done with
>
> lxc-destroy -P /var/lib/lxcsnaps/c1 -n snap2
>
> so I leave it to others to decide whether they really want
> it, and provide the patch if so.
>
> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>
Simple works for me :)
Acked-by: Stéphane Graber <stgraber at ubuntu.com>
> ---
> src/lxc/Makefile.am | 4 +-
> src/lxc/lxc_snapshot.c | 201 +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 204 insertions(+), 1 deletion(-)
> create mode 100644 src/lxc/lxc_snapshot.c
>
> diff --git a/src/lxc/Makefile.am b/src/lxc/Makefile.am
> index da5ff15..35ec2a3 100644
> --- a/src/lxc/Makefile.am
> +++ b/src/lxc/Makefile.am
> @@ -171,7 +171,8 @@ bin_PROGRAMS = \
> lxc-config \
> lxc-destroy \
> lxc-create \
> - lxc-user-nic
> + lxc-user-nic \
> + lxc-snapshot
>
> if HAVE_NEWUIDMAP
> bin_PROGRAMS += lxc-usernsexec
> @@ -207,6 +208,7 @@ lxc_unshare_SOURCES = lxc_unshare.c
> lxc_wait_SOURCES = lxc_wait.c
> lxc_kill_SOURCES = lxc_kill.c
> lxc_create_SOURCES = lxc_create.c
> +lxc_snapshot_SOURCES = lxc_snapshot.c
> lxc_usernsexec_SOURCES = lxc_usernsexec.c
> lxc_user_nic_SOURCES = lxc_user_nic.c
>
> diff --git a/src/lxc/lxc_snapshot.c b/src/lxc/lxc_snapshot.c
> new file mode 100644
> index 0000000..2222972
> --- /dev/null
> +++ b/src/lxc/lxc_snapshot.c
> @@ -0,0 +1,201 @@
> +/*
> + *
> + * Copyright © 2013 Serge Hallyn <serge.hallyn at ubuntu.com>.
> + * Copyright © 2013 Canonical Ltd.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2, as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, write to the Free Software Foundation, Inc.,
> + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
> + */
> +
> +#include "../lxc/lxccontainer.h"
> +
> +#include <stdio.h>
> +#include <libgen.h>
> +#include <unistd.h>
> +#include <ctype.h>
> +#include <sys/types.h>
> +
> +#include <lxc/lxc.h>
> +#include <lxc/log.h>
> +#include <lxc/bdev.h>
> +
> +#include "arguments.h"
> +#include "utils.h"
> +
> +lxc_log_define(lxc_snapshot, lxc);
> +
> +char *newname;
> +char *snapshot;
> +
> +#define DO_SNAP 0
> +#define DO_LIST 1
> +#define DO_RESTORE 2
> +int action;
> +int print_comments;
> +char *commentfile;
> +
> +int do_snapshot(struct lxc_container *c)
> +{
> + int ret;
> +
> + ret = c->snapshot(c, commentfile);
> + if (ret < 0) {
> + ERROR("Error creating a snapshot");
> + return -1;
> + }
> +
> + INFO("Created snapshot snap%d\n", ret);
> + return 0;
> +}
> +
> +void print_file(char *path)
> +{
> + if (!path)
> + return;
> + FILE *f = fopen(path, "r");
> + char *line = NULL;
> + size_t sz = 0;
> + if (!f)
> + return;
> + while (getline(&line, &sz, f) != -1) {
> + printf("%s", line);
> + }
> + if (line)
> + free(line);
> + fclose(f);
> +}
> +
> +int do_list_snapshots(struct lxc_container *c)
> +{
> + struct lxc_snapshot *s;
> + int i, n;
> +
> + n = c->snapshot_list(c, &s);
> + if (n < 0) {
> + ERROR("Error listing snapshots");
> + return -1;
> + }
> + if (n == 0) {
> + printf("No snapshots\n");
> + return 0;
> + }
> + for (i=0; i<n; i++) {
> + printf("%s (%s) %s\n", s[i].name, s[i].lxcpath, s[i].timestamp);
> + if (print_comments)
> + print_file(s[i].comment_pathname);
> + s[i].free(&s[i]);
> + }
> + free(s);
> + return 0;
> +}
> +
> +int do_restore_snapshots(struct lxc_container *c, char *snap, char *new)
> +{
> + if (c->snapshot_restore(c, snapshot, newname))
> + return 0;
> +
> + ERROR("Error restoring snapshot %s", snapshot);
> + return -1;
> +}
> +
> +static int my_parser(struct lxc_arguments* args, int c, char* arg)
> +{
> + switch (c) {
> + case 'L': action = DO_LIST; break;
> + case 'r': snapshot = arg; action = DO_RESTORE; break;
> + case 'c': commentfile = arg; break;
> + case 'C': print_comments = true; break;
> + }
> + return 0;
> +}
> +
> +static const struct option my_longopts[] = {
> + {"list", no_argument, 0, 'L'},
> + {"restore", required_argument, 0, 'r'},
> + {"comment", required_argument, 0, 'c'},
> + {"showcomments", no_argument, 0, 'C'},
> + LXC_COMMON_OPTIONS
> +};
> +
> +
> +static struct lxc_arguments my_args = {
> + .progname = "lxc-create",
> + .help = "\
> +--name=NAME [-w] [-r] [-t timeout] [-P lxcpath]\n\
> +\n\
> +lxc-create creates a container\n\
> +\n\
> +Options :\n\
> + -L, --list list snapshots\n\
> + -C, --showcomments show snapshot comments in list\n\
> + -c, --comment=file add file as a comment\n\
> + -r, --restore=name restore snapshot name, i.e. 'snap0'\n",
> + .options = my_longopts,
> + .parser = my_parser,
> + .checker = NULL,
> +};
> +
> +/*
> + * lxc-snapshot -P lxcpath -n container
> + * lxc-snapshot -P lxcpath -n container -l
> + * lxc-snapshot -P lxcpath -n container -r snap3 recovered_1
> + */
> +
> +int main(int argc, char *argv[])
> +{
> + struct lxc_container *c;
> + int ret = 0;
> +
> + if (lxc_arguments_parse(&my_args, argc, argv))
> + exit(1);
> +
> + if (my_args.argc > 1) {
> + ERROR("Too many arguments");
> + return -1;
> + }
> + if (my_args.argc == 1)
> + newname = my_args.argv[0];
> +
> + if (lxc_log_init(my_args.name, my_args.log_file, my_args.log_priority,
> + my_args.progname, my_args.quiet, my_args.lxcpath[0]))
> + exit(1);
> +
> + if (geteuid()) {
> + if (access(my_args.lxcpath[0], O_RDWR) < 0) {
> + fprintf(stderr, "You lack access to %s\n", my_args.lxcpath[0]);
> + exit(1);
> + }
> + }
> +
> + c = lxc_container_new(my_args.name, my_args.lxcpath[0]);
> + if (!c) {
> + fprintf(stderr, "System error loading container\n");
> + exit(1);
> + }
> +
> + switch(action) {
> + case DO_SNAP:
> + ret = do_snapshot(c);
> + break;
> + case DO_LIST:
> + ret = do_list_snapshots(c);
> + break;
> + case DO_RESTORE:
> + ret = do_restore_snapshots(c, snapshot, newname);
> + break;
> + }
> +
> + lxc_container_put(c);
> +
> + exit(ret);
> +}
> --
> 1.8.1.2
>
>
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--
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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