[CRIU] Attempt for process migration
Adrian Reber
adrian at lisas.de
Tue Mar 6 06:19:31 EST 2012
I have been successfully using criu. Now I looked into migrating one
process from one machine to another. I written some code but before I am
going to continue I wanted to ask if there has been already any
discussion in that direction? Also, the current code makes it hard to
implement migration over TCP and therefore I wanted some feedback before
continuing. Not that I am doing it completely wrong. Attached is a patch
which I am using to write the image to another machine.
It basically works that way:
* user supplies with -r [host:port] on which machine a server is
listening to receive the checkpoint image
* after that I changed cr_fdset_open() to open a socket instead of
a file to which the checkpoint can be transferred
So far it still seems correct. Unfortunately I had to add at the opts
structure to many functions as parameter to have it available in the
cr_fdset_open() function. The problem I have with cr_fdset_open() is
that it is writing the magic string just after the file has been opened
and that is something I cannot do with the socket if I want to use only
one TCP connection for the complete migration. Would it be somehow
possible to move the writing of the magic string to the low level
write_img_buf() function? Is it at all possible with the current code to
use one socket to write all images serialized over the network to
another machine?
Does it make any sense how I started with this?
Are there ideas how correctly implement this?
Adrian
-------------- next part --------------
diff --git a/cr-dump.c b/cr-dump.c
index c4d62fe..49452ff 100644
--- a/cr-dump.c
+++ b/cr-dump.c
@@ -1222,11 +1222,11 @@ err:
}
static int dump_one_zombie(struct pstree_item *item, struct proc_pid_stat *pps,
- struct cr_fdset *cr_fdset)
+ struct cr_fdset *cr_fdset, struct cr_options *opts)
{
struct core_entry *core;
- cr_fdset = cr_dump_fdset_open(item->pid, CR_FD_DESC_CORE, cr_fdset);
+ cr_fdset = cr_dump_fdset_open(item->pid, CR_FD_DESC_CORE, cr_fdset, opts);
if (cr_fdset == NULL)
return -1;
@@ -1243,7 +1243,7 @@ static int dump_one_zombie(struct pstree_item *item, struct proc_pid_stat *pps,
static struct proc_pid_stat pps_buf;
static int dump_task_threads(struct parasite_ctl *parasite_ctl,
- struct pstree_item *item)
+ struct pstree_item *item, struct cr_options *opts)
{
int i;
struct cr_fdset *cr_fdset_thread = NULL;
@@ -1256,7 +1256,7 @@ static int dump_task_threads(struct parasite_ctl *parasite_ctl,
if (item->pid == item->threads[i])
continue;
- cr_fdset_thread = cr_dump_fdset_open(item->threads[i], CR_FD_DESC_CORE, NULL);
+ cr_fdset_thread = cr_dump_fdset_open(item->threads[i], CR_FD_DESC_CORE, NULL, opts);
if (!cr_fdset_thread)
goto err;
@@ -1274,7 +1274,7 @@ err:
return -1;
}
-static int dump_one_task(struct pstree_item *item, struct cr_fdset *cr_fdset)
+static int dump_one_task(struct pstree_item *item, struct cr_fdset *cr_fdset, struct cr_options *opts)
{
pid_t pid = item->pid;
LIST_HEAD(vma_area_list);
@@ -1298,10 +1298,10 @@ static int dump_one_task(struct pstree_item *item, struct cr_fdset *cr_fdset)
goto err;
if (item->state == TASK_DEAD)
- return dump_one_zombie(item, &pps_buf, cr_fdset);
+ return dump_one_zombie(item, &pps_buf, cr_fdset, opts);
ret = -1;
- if (!cr_dump_fdset_open(item->pid, CR_FD_DESC_TASK, cr_fdset))
+ if (!cr_dump_fdset_open(item->pid, CR_FD_DESC_TASK, cr_fdset, opts))
goto err;
ret = collect_mappings(pid, &vma_area_list);
@@ -1352,7 +1352,7 @@ static int dump_one_task(struct pstree_item *item, struct cr_fdset *cr_fdset)
goto err;
}
- ret = dump_task_threads(parasite_ctl, item);
+ ret = dump_task_threads(parasite_ctl, item, opts);
if (ret) {
pr_err("Can't dump threads\n");
goto err;
@@ -1415,7 +1415,7 @@ int cr_dump_tasks(pid_t pid, struct cr_options *opts)
goto err;
if (opts->namespaces_flags) {
- ret = dump_namespaces(pid, opts->namespaces_flags);
+ ret = dump_namespaces(pid, opts);
if (ret < 0)
goto err;
}
@@ -1430,12 +1430,12 @@ int cr_dump_tasks(pid_t pid, struct cr_options *opts)
collect_sockets();
list_for_each_entry(item, &pstree_list, list) {
- cr_fdset = cr_dump_fdset_open(item->pid, CR_FD_DESC_NONE, NULL);
+ cr_fdset = cr_dump_fdset_open(item->pid, CR_FD_DESC_NONE, NULL, opts);
if (!cr_fdset)
goto err;
if (item->pid == pid) {
- if (!cr_dump_fdset_open(item->pid, CR_FD_DESC_USE(CR_FD_PSTREE), cr_fdset))
+ if (!cr_dump_fdset_open(item->pid, CR_FD_DESC_USE(CR_FD_PSTREE), cr_fdset, opts))
goto err;
if (dump_pstree(pid, &pstree_list, cr_fdset))
goto err;
@@ -1448,10 +1448,10 @@ int cr_dump_tasks(pid_t pid, struct cr_options *opts)
* That's why we open the file with tree leader's pid for any
* of it's children.
*/
- if (!cr_dump_fdset_open(pid, CR_FD_DESC_USE(CR_FD_SK_QUEUES), cr_fdset))
+ if (!cr_dump_fdset_open(pid, CR_FD_DESC_USE(CR_FD_SK_QUEUES), cr_fdset, opts))
goto err;
- if (dump_one_task(item, cr_fdset))
+ if (dump_one_task(item, cr_fdset, opts))
goto err;
close_cr_fdset(&cr_fdset);
diff --git a/cr-show.c b/cr-show.c
index eeb7042..28a5f9e 100644
--- a/cr-show.c
+++ b/cr-show.c
@@ -551,7 +551,7 @@ static int cr_show_all(unsigned long pid, struct cr_options *opts)
LIST_HEAD(pstree_list);
int i, ret = -1;
- cr_fdset = cr_show_fdset_open(pid, CR_FD_DESC_PSTREE | CR_FD_DESC_SK_QUEUES);
+ cr_fdset = cr_show_fdset_open(pid, CR_FD_DESC_PSTREE | CR_FD_DESC_SK_QUEUES, opts);
if (!cr_fdset)
goto out;
@@ -565,13 +565,13 @@ static int cr_show_all(unsigned long pid, struct cr_options *opts)
close_cr_fdset(&cr_fdset);
- ret = try_show_namespaces(pid);
+ ret = try_show_namespaces(pid, opts);
if (ret)
goto out;
list_for_each_entry(item, &pstree_list, list) {
- cr_fdset = cr_show_fdset_open(item->pid, CR_FD_DESC_TASK);
+ cr_fdset = cr_show_fdset_open(item->pid, CR_FD_DESC_TASK, opts);
if (!cr_fdset)
goto out;
@@ -586,7 +586,7 @@ static int cr_show_all(unsigned long pid, struct cr_options *opts)
if (item->threads[i] == item->pid)
continue;
- cr_fdset_th = cr_show_fdset_open(item->threads[i], CR_FD_DESC_CORE);
+ cr_fdset_th = cr_show_fdset_open(item->threads[i], CR_FD_DESC_CORE, opts);
if (!cr_fdset_th)
goto out;
diff --git a/crtools.c b/crtools.c
index 469a7b3..2640474 100644
--- a/crtools.c
+++ b/crtools.c
@@ -6,6 +6,7 @@
#include <getopt.h>
#include <string.h>
#include <ctype.h>
+#include <netdb.h>
#include <fcntl.h>
@@ -142,6 +143,34 @@ struct cr_fd_desc_tmpl fdset_template[CR_FD_MAX] = {
},
};
+static int open_socket(char *hostname, int portno)
+{
+ static int sockfd = -1;
+ struct hostent *server;
+ struct sockaddr_in serveraddr;
+
+ if (sockfd != -1)
+ return sockfd;
+
+ sockfd = socket(AF_INET, SOCK_STREAM, 0);
+ if (sockfd < 0)
+ pr_perror("ERROR opening socket");
+
+ server = gethostbyname(hostname);
+ if (server == NULL)
+ pr_perror("ERROR, no such host as %s\n", hostname);
+
+ memset((char *) &serveraddr, 0, sizeof(serveraddr));
+ serveraddr.sin_family = AF_INET;
+ memcpy((char *)&serveraddr.sin_addr.s_addr,(char *)server->h_addr, server->h_length);
+ serveraddr.sin_port = htons(portno);
+
+ if (connect(sockfd, (struct sockaddr *)&serveraddr, sizeof(serveraddr)) < 0)
+ pr_perror("ERROR connecting\n");
+
+ return sockfd;
+}
+
static struct cr_fdset *alloc_cr_fdset(void)
{
struct cr_fdset *cr_fdset;
@@ -181,7 +210,8 @@ void close_cr_fdset(struct cr_fdset **cr_fdset)
}
static struct cr_fdset *cr_fdset_open(int pid, unsigned long use_mask,
- unsigned long flags, struct cr_fdset *cr_fdset)
+ unsigned long flags, struct cr_fdset *cr_fdset,
+ struct cr_options *opts)
{
struct cr_fdset *fdset;
unsigned int i;
@@ -205,6 +235,11 @@ static struct cr_fdset *cr_fdset_open(int pid, unsigned long use_mask,
if (fdset->fds[i] != -1)
continue;
+ if (opts->host && (opts->port > 0)) {
+ fdset->fds[i] = open_socket(opts->host, opts->port);
+ continue;
+ }
+
ret = get_image_path(path, sizeof(path),
fdset_template[i].fmt, pid);
if (ret)
@@ -254,15 +289,17 @@ err:
}
struct cr_fdset *cr_dump_fdset_open(int pid, unsigned long use_mask,
- struct cr_fdset *cr_fdset)
+ struct cr_fdset *cr_fdset,
+ struct cr_options *opts)
{
return cr_fdset_open(pid, use_mask, O_RDWR | O_CREAT | O_EXCL,
- cr_fdset);
+ cr_fdset, opts);
}
-struct cr_fdset *cr_show_fdset_open(int pid, unsigned long use_mask)
+struct cr_fdset *cr_show_fdset_open(int pid, unsigned long use_mask,
+ struct cr_options *opts)
{
- return cr_fdset_open(pid, use_mask, O_RDONLY, NULL);
+ return cr_fdset_open(pid, use_mask, O_RDONLY, NULL, opts);
}
static int parse_ns_string(const char *ptr, unsigned int *flags)
@@ -296,7 +333,7 @@ int main(int argc, char *argv[])
int log_inited = 0;
int log_level = 0;
- static const char short_opts[] = "dsf:p:t:hcD:o:n:v";
+ static const char short_opts[] = "dsf:p:t:hcD:o:n:vr:";
BUILD_BUG_ON(PAGE_SIZE != PAGE_IMAGE_SIZE);
@@ -365,6 +402,17 @@ int main(int argc, char *argv[])
log_level++;
}
break;
+ case 'r':
+ opts.host = strchr(optarg, ':');
+ if (!opts.host)
+ goto usage;
+ /* port needs to be at least one digit long after ':' */
+ if (strlen(optarg) < strchr(optarg, ':') - optarg + 2)
+ goto usage;
+ opts.port = atoi(strchr(optarg, ':') + 1);
+ optarg[strchr(optarg, ':') - optarg] = 0;
+ opts.host = strdup(optarg);
+ break;
case 'h':
default:
goto usage;
@@ -441,6 +489,7 @@ usage:
pr_msg("\nAdditional common parameters:\n");
pr_msg(" -D dir save checkpoint files in specified directory\n");
+ pr_msg(" -r [host:port] write checkpoint to remote host:port\n");
pr_msg(" -v [num] set logging level\n");
pr_msg(" 0 - silent (only error messages)\n");
pr_msg(" 1 - informative (default)\n");
diff --git a/include/crtools.h b/include/crtools.h
index 795626f..7370461 100644
--- a/include/crtools.h
+++ b/include/crtools.h
@@ -54,6 +54,8 @@ struct cr_options {
bool show_pages_content;
bool restore_detach;
unsigned int namespaces_flags;
+ char *host;
+ int port;
};
/* file descriptors template */
@@ -127,8 +129,8 @@ int cr_show(unsigned long pid, struct cr_options *opts);
int convert_to_elf(char *elf_path, int fd_core);
int cr_check(void);
-struct cr_fdset *cr_dump_fdset_open(int pid, unsigned long use_mask, struct cr_fdset *);
-struct cr_fdset *cr_show_fdset_open(int pid, unsigned long use_mask);
+struct cr_fdset *cr_dump_fdset_open(int pid, unsigned long use_mask, struct cr_fdset *, struct cr_options *opts);
+struct cr_fdset *cr_show_fdset_open(int pid, unsigned long use_mask, struct cr_options *opts);
void close_cr_fdset(struct cr_fdset **cr_fdset);
void free_mappings(struct list_head *vma_area_list);
diff --git a/include/namespaces.h b/include/namespaces.h
index 9e0c04f..40dc820 100644
--- a/include/namespaces.h
+++ b/include/namespaces.h
@@ -1,7 +1,9 @@
+#include "crtools.h"
+
#ifndef __CR_NS_H__
#define __CR_NS_H__
-int dump_namespaces(int pid, unsigned int ns_flags);
+int dump_namespaces(int pid, struct cr_options *opts);
int prepare_namespace(int pid, unsigned long clone_flags);
-int try_show_namespaces(int pid);
+int try_show_namespaces(int pid, struct cr_options *opts);
int switch_ns(int pid, int type, char *ns);
#endif
diff --git a/namespaces.c b/namespaces.c
index b64f9b0..2c01db9 100644
--- a/namespaces.c
+++ b/namespaces.c
@@ -28,12 +28,12 @@ out:
return ret;
}
-static int do_dump_namespaces(int ns_pid, unsigned int ns_flags)
+static int do_dump_namespaces(int ns_pid, unsigned int ns_flags, struct cr_options *opts)
{
struct cr_fdset *fdset;
int ret = 0;
- fdset = cr_dump_fdset_open(ns_pid, CR_FD_DESC_NS, NULL);
+ fdset = cr_dump_fdset_open(ns_pid, CR_FD_DESC_NS, NULL, opts);
if (fdset == NULL)
return -1;
@@ -55,10 +55,11 @@ err:
}
-int dump_namespaces(int ns_pid, unsigned int ns_flags)
+int dump_namespaces(int ns_pid, struct cr_options *opts)
{
int pid, status;
int ret = 0;
+ unsigned int ns_flags = opts->namespaces_flags;
/*
* The setns syscall is cool, we can switch to the other
@@ -80,7 +81,7 @@ int dump_namespaces(int ns_pid, unsigned int ns_flags)
}
if (pid == 0) {
- ret = do_dump_namespaces(ns_pid, ns_flags);
+ ret = do_dump_namespaces(ns_pid, ns_flags, opts);
exit(ret);
}
@@ -114,11 +115,11 @@ int prepare_namespace(int pid, unsigned long clone_flags)
return ret;
}
-int try_show_namespaces(int ns_pid)
+int try_show_namespaces(int ns_pid, struct cr_options *opts)
{
struct cr_fdset *fdset;
- fdset = cr_show_fdset_open(ns_pid, CR_FD_DESC_NS);
+ fdset = cr_show_fdset_open(ns_pid, CR_FD_DESC_NS, opts);
if (!fdset)
return -1;
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