/usr/bin/kvm(QEMU) \
……\
-device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x6 \
-device isa-serial,chardev=charserial1,id=serial1 \
-chardev socket,id=charchannel0,path=/var/lib/libvirt/qemu/test.agent,server,nowait \
-device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,\
name=com.163.spice.0

<channel type='unix'>
   <source mode='bind' path='/var/lib/libvirt/qemu/test.agent'/>
   <target type='virtio' name='com.163.spice.0'/>
 </channel>

Ø guest-sync-delimited*：宿主机发送一个int数字给qga，qga返回这个数字，并且在后续返回字符串响应中加入ascii码为0xff的字符，其作用是检查宿主机与qga通信的同步状态，主要用在宿主机上多客户端与qga通信的情况下客户端间切换过程的状态同步检查，比如有两个客户端A、B，qga发送给A的响应，由于A已经退出，目前B连接到qga的socket，所以这个响应可能被B收到，如果B连接到socket之后，立即发送该请求给qga，响应中加入了这个同步码就能区分是A的响应还是B的响应；在qga返回宿主机客户端发送的int数字之前，qga返回的所有响应都要忽略；


Ø guest-sync*：与上面相同，只是不在响应中加入0xff字符；


Ø guest-ping*：Ping the guest agent, a non-error return implies success；


Ø guest-get-time*：获取虚拟机时间（返回值为相对于1970-01-01 in UTC，Time in nanoseconds.）；


Ø guest-set-time*：设置虚拟机时间（输入为相对于1970-01-01 in UTC，Time in nanoseconds.）；


Ø guest-info*：返回qga支持的所有命令；


Ø guest-shutdown*：关闭虚拟机（支持halt、powerdown、reboot，默认动作为powerdown）；


Ø guest-file-open：打开虚拟机内的某个文件（返回文件句柄）；


Ø guest-file-close：关闭打开的虚拟机内的文件；


Ø guest-file-read：根据文件句柄读取虚拟机内的文件内容（返回base64格式的文件内容）；


Ø guest-file-write：根据文件句柄写入文件内容到虚拟机内的文件；


Ø guest-file-seek：Seek to a position in the file, as with fseek(), and return the current file position afterward. Also encapsulates ftell()'s functionality, just Set offset=0, whence=SEEK_CUR；


Ø guest-file-flush：Write file changes bufferred in userspace to disk/kernel buffers；


Ø guest-fsfreeze-status：Get guest fsfreeze state. error state indicates；


Ø guest-fsfreeze-freeze：Sync and freeze all freezable, local guest filesystems；


Ø guest-fsfreeze-thaw：Unfreeze all frozen guest filesystems；


Ø guest-fstrim：Discard (or "trim") blocks which are not in use by the filesystem；


Ø guest-suspend-disk*：Suspend guest to disk；


Ø guest-suspend-ram*：Suspend guest to ram；


Ø guest-suspend-hybrid：Save guest state to disk and suspend to ram（This command requires the pm-utils package to be installed in the guest.）；


Ø guest-network-get-interfaces：Get list of guest IP addresses, MAC addresses and netmasks；


Ø guest-get-vcpus：Retrieve the list of the guest's logical processors；


guest-set-vcpus：Attempt to reconfigure (currently: enable/disable) logical processors inside the guest。

diff --git a/qga/commands-posix.c b/qga/commands-posix.c
index e199738..2f42a2f 100644
--- a/qga/commands-posix.c
+++ b/qga/commands-posix.c
@@ -21,6 +21,7 @@
 #include <stdio.h>
 #include <string.h>
 #include <sys/stat.h>
+#include <sys/statvfs.h>
 #include <inttypes.h>
 #include "qga/guest-agent-core.h"
 #include "qga-qmp-commands.h"
@@ -1467,6 +1468,36 @@ void qmp_guest_fstrim(bool has_minimum, int64_t minimum, Error **err)
 }
 #endif
 
+GuestFileSystemStatistics *qmp_guest_get_statvfs(const char *path, Error **errp)
+{
+    int ret;
+    GuestFileSystemStatistics *fs_stat;
+    struct statvfs *buf;
+    buf = g_malloc0(sizeof(struct statvfs));
+
+
+    ret = statvfs(path, buf);
+    if (ret < 0) {
+       error_setg_errno(errp, errno, "Failed to get statvfs");
+       return NULL;
+    }
+
+    fs_stat = g_malloc0(sizeof(GuestFileSystemStatistics));
+    fs_stat->f_bsize = buf->f_bsize;
+    fs_stat->f_frsize = buf->f_frsize;
+    fs_stat->f_blocks = buf->f_blocks;
+    fs_stat->f_bfree = buf->f_bfree;
+    fs_stat->f_bavail = buf->f_bavail;
+    fs_stat->f_files = buf->f_files;
+    fs_stat->f_ffree = buf->f_ffree;
+    fs_stat->f_favail = buf->f_favail;
+    fs_stat->f_fsid = buf->f_fsid;
+    fs_stat->f_flag = buf->f_flag;
+    fs_stat->f_namemax = buf->f_namemax;
+
+    return fs_stat;
+}
+
 /* register init/cleanup routines for stateful command groups */
 void ga_command_state_init(GAState *s, GACommandState *cs)
 {
diff --git a/qga/qapi-schema.json b/qga/qapi-schema.json
index 7155b7a..a071c3f 100644
--- a/qga/qapi-schema.json
+++ b/qga/qapi-schema.json
@@ -638,3 +638,52 @@
 { 'command': 'guest-set-vcpus',
   'data':    {'vcpus': ['GuestLogicalProcessor'] },
   'returns': 'int' }
+
+##
+# @GuestFileSystemStatistics:
+#
+# Information about guest file system statistics.
+#
+# @f_bsize: file system block size.
+#
+# @f_frsize: fragment size.
+#
+# @f_blocks: size of fs in f_frsize units.
+#
+# @f_bfree: free blocks.
+#
+# @f_bavail: free blocks for non-root.
+#
+# @f_files: inodes.
+#
+# @f_ffree: free inodes.
+#
+# @f_favail: free inodes for non-root.
+#
+# @f_fsid: file system id.
+#
+# @f_flag: mount flags
+#
+# @f_namemax: maximum filename length.
+#
+# Since 1.5.10(NetEase)
+##
+{ 'type': 'GuestFileSystemStatistics',
+  'data': { 'f_bsize': 'int', 'f_frsize': 'int', 'f_blocks': 'int',
+            'f_bfree': 'int', 'f_bavail': 'int', 'f_files': 'int',
+            'f_ffree': 'int', 'f_favail': 'int', 'f_fsid': 'int',
+            'f_flag': 'int', 'f_namemax': 'int'} }
+
+##
+# @guest-get-statvfs:
+#
+# Get the information about guest file system statistics by statvfs.
+#
+# Returns: @GuestFileSystemStatistics.
+#
+# Since 1.5.10(NetEase)
+##
+{ 'command': 'guest-get-statvfs',
+  'data':    { 'path': 'str' },
+  'returns': 'GuestFileSystemStatistics' }
+

• 依赖云主机内部的python解释器
• 云主机必须存在root账户
• 依赖NVS文件注入功能；并且为了注入这些监控文件对nova的改动也比较大，也无法与社区同步；windows镜像也会注入这些无用的文件，可能导致一些意想不到的问题；另外如果有的镜像的操作系统不在第一个分区上，则注入的监控文件会失效
• 已经运行的云主机内部的监控相关文件更新困难，导致新监控项的添加、推送周期、推送地址等的修改也比较困难，灵活性较差
• Nova中base64编码的注入脚本的代码可读性很差，代码更新及维护困难
• 定位问题一般都需要登录到云主机内部进行，对于采用密钥对登录的云主机来说定位问题比较困难