libvirt 獲取 guest賬戶的IP方案
方案
目前找到兩種方案。方案一：libvirt命令獲取。 方案二：調用libvirt-api獲取。
方案一：virsh 命令
相關命令如下：
virsh #進入virsh 命令模式
list --all # 查看所有在線的虛擬機列表
虛擬機列表輸出結果如下：
Id Name State
----------------------------------------------------
1 151 running
- 170 shut off
- win10 shut off
可以看出正在運行的虛擬機 爲 151
查看151支持的相關命令
qemu-agent-command 151 '{"execute":"guest-info"}'
輸出結果如下：
{"return":{"version":"0.12.1","supported_commands":[{"enabled":true,"name":"guest-set-user-password"},{"enabled":true,"name":"guest-get-vcpus"},{"enabled":true,"name":"guest-suspend-ram"},{"enabled":true,"name":"guest-suspend-disk"},{"enabled":true,"name":"guest-fsfreeze-thaw"},{"enabled":true,"name":"guest-fsfreeze-freeze"},{"enabled":true,"name":"guest-fsfreeze-status"},{"enabled":true,"name":"guest-shutdown"},{"enabled":true,"name":"guest-info"},{"enabled":true,"name":"guest-set-time"},{"enabled":true,"name":"guest-get-time"},{"enabled":true,"name":"guest-ping"},{"enabled":true,"name":"guest-sync"},{"enabled":true,"name":"guest-sync-delimited"}]}}
獲取虛擬機IP的主要命令如下：
qemu-agent-command 151 '{"execute":"guest-network-get-interfaces"}'
輸出結果如下：
{"return":[{"name":"��̫��e","ip-addresses":[{"ip-address-type":"ipv6","ip-address":"fe80::9ded:74ad:cbc9:7ec2%5","prefix":64},{"ip-address-type":"ipv4","ip-address":"172.26.106.102","prefix":24}],"statistics":{"tx-packets":183723,"tx-errs":0,"rx-bytes":482140384,"rx-dropped":4781392,"rx-packets":329018,"rx-errs":0,"tx-bytes":12037307,"tx-dropped":0},"hardware-address":"52:54:00:89:0e:2b"},{"name":"Loopback Pseudo-Interface 1","ip-addresses":[{"ip-address-type":"ipv6","ip-address":"::1","prefix":128},{"ip-address-type":"ipv4","ip-address":"127.0.0.1","prefix":8}],"statistics":{"tx-packets":0,"tx-errs":0,"rx-bytes":0,"rx-dropped":0,"rx-packets":0,"rx-errs":0,"tx-bytes":0,"tx-dropped":0}},{"name":"Teredo Tunneling Pseudo-Interface","ip-addresses":[{"ip-address-type":"ipv6","ip-address":"2001:0:348b:fb58:28bf:26c3:2ca1:2326","prefix":64},{"ip-address-type":"ipv6","ip-address":"fe80::28bf:26c3:2ca1:2326%3","prefix":64}],"statistics":{"tx-packets":165,"tx-errs":0,"rx-bytes":18504,"rx-dropped":0,"rx-packets":191,"rx-errs":0,"tx-bytes":18780,"tx-dropped":0},"hardware-address":"00:00:00:00:00:00"}]}
所有相關的ip信息如下： ip地址類型，ip地址，硬件地址
方案二：調用API接口
官方接口地址：https://libvirt.org/html/libvirt-libvirt-domain.html#virDomainIPAddress
相關結構體如下：
struct virDomainIPAddress { //ip信息結構體
int type; //virIPAddrType
char * addr; //IP address
unsigned int prefix; //IP address prefix
}
struct virDomainInterface { //接口信息結構體
char * name; //interface name
char * hwaddr; //hardware address, may be NULL
unsigned int naddrs; //number of items in @addrs
virDomainIPAddressPtr addrs; //array of IP addresses
}
/*
Return a pointer to the allocated array of pointers to interfaces present in given domain along with their IP and MAC addresses. Note that single interface can have multiple or even 0 IP addresses
*/
int virDomainInterfaceAddresses (virDomainPtr dom,
virDomainInterfacePtr ** ifaces,
unsigned int source,
unsigned int flags) //interface接口地址獲取方法
enum virDomainInterfaceAddressesSource { //ip地址的枚舉類型
VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LEASE = 0 (0x0) ,//Parse DHCP lease file
VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_AGENT = 1 (0x1) ,//Query qemu guest agent
VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_ARP = 2 (0x2) ,//Query ARP tables
VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LAST = 3 (0x3)
}
目前筆者用的 類型爲 VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_AGENT ，獲取指定虛擬機IP。 VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LEASE爲獲取 DHCP 方式的虛擬機IP。VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_ARP，VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LAST這兩種類型，筆者的libvirt版本不支持也就沒有測試。
官方Demo樣例如下：
virDomainInterfacePtr *ifaces = NULL; //接口指針初始化 --網卡
int ifaces_count = 0; //接口個數
size_t i, j;
virDomainPtr dom = /*... obtain a domain here ...*/;
if ((ifaces_count = virDomainInterfaceAddresses(dom, &ifaces,
VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_LEASE)) < 0)
goto cleanup;
//... do something with returned values, for example:
for (i = 0; i < ifaces_count; i++) {
printf("name: %s", ifaces[i]->name);
if (ifaces[i]->hwaddr) //網卡個數，硬件地址 MAC
printf(" hwaddr: %s", ifaces[i]->hwaddr);
for (j = 0; j < ifaces[i]->naddrs; j++) {
virDomainIPAddressPtr ip_addr = ifaces[i]->addrs + j;
printf("[addr: %s prefix: %d type: %d]",
ip_addr->addr, ip_addr->prefix, ip_addr->type);
}
printf("\n");
}
cleanup:
if (ifaces && ifaces_count > 0)
for (i = 0; i < ifaces_count; i++)
virDomainInterfaceFree(ifaces[i]);
free(ifaces);//釋放接口指針內存
/*參數說明
dom: domain object
ifaces: pointer to an array of pointers pointing to interface objects
source: one of the virDomainInterfaceAddressesSource constants
flags: currently unused, pass zero
Returns: the number of interfaces on success, -1 in case of error.
*/
測試代碼如下：
#include <stdio.h>
#include <stdlib.h>
#include <libvirt/libvirt.h>
#include <libvirt/virterror.h>
#include <libvirt/libvirt-domain.h>
#include <string.h>
#define MAX_LEN (1024*10)
int main(int argc, char** argv)
{
virConnectPtr conn;
virDomainInterfacePtr* ifaces = NULL;
int ret = -1;
int ifaces_count = 0;
int i,j;
conn = virConnectOpen("qemu:///system");
if(conn == NULL){
printf("failed to open connection to qemu\n");
return 1;
}
printf("success to open connection to qemu\n");
char* xml = malloc(MAX_LEN);
memset(xml,0,MAX_LEN);
FILE* fp = NULL;
//filename 作者寫爲了固定地址。也可以利用 argv參數進行傳參
char filename[128] = {"/etc/libvirt/qemu/151.xml"};
fp = fopen(filename,"r");
if(fp != NULL){
int len = fread(xml,1,MAX_LEN,fp);
printf("len = %d\n",len);
}
else{
printf("fp is null!\n");
}
if(fp != NULL){
fclose(fp);
}
virDomainPtr dom;
dom = virDomainDefineXML(conn,xml);
if(!dom){
printf("domain definition failed\n");
}
if((ifaces_count = virDomainInterfaceAddresses(dom,&ifaces,VIR_DOMAIN_INTERFACE_ADDRESSES_SRC_AGENT ,0))<0)
{
goto cleanup;
}
for( i=0;i<ifaces_count;i++)
{
printf("name:%s \n",ifaces[i]->name);
if(ifaces[i]->hwaddr) printf("hwaddr:%s\n",ifaces[i]->hwaddr);
for( j = 0;j < ifaces[i]->naddrs;j++)
{
virDomainIPAddressPtr ip_addr = ifaces[i]->addrs + j;
printf("[addr: %s prefix: %d type: %d]\n",
ip_addr->addr, ip_addr->prefix, ip_addr->type);
}
}
cleanup:
if (ifaces && ifaces_count > 0)
for (i = 0; i < ifaces_count; i++)
virDomainInterfaceFree(ifaces[i]);
free(ifaces);
return ret;
}
編譯：
gcc add.c -lvirt -o add
輸出結果如下：
success to open connection to qemu
len = 4214
name:��̫��e
hwaddr:52:54:00:89:0e:2b
[addr: fe80::9ded:74ad:cbc9:7ec2%5 prefix: 64 type: 1]
[addr: 172.26.106.102 prefix: 24 type: 0]
name:Loopback Pseudo-Interface 1
[addr: ::1 prefix: 128 type: 1]
[addr: 127.0.0.1 prefix: 8 type: 0]
name:Teredo Tunneling Pseudo-Interface
hwaddr:00:00:00:00:00:00
[addr: fe80::ffff:ffff:fffe%3 prefix: 64 type: 1]
相關錯誤解決方法：
-
錯誤一：
libvirt: QEMU Driver error : internal error: unable to execute QEMU agent command 'guest-network-get-interfaces': The command guest-network-get-interfaces has been disabled for this instance解決方法：
1.查看命令是否啓用。網絡上黑白名單，但是作者是 ubuntu 系統，並沒有找到相關的json文件。查看命令是否被禁用，如果被禁用，則啓用。 2.利用 qemu-agent-command 151 '{"execute":"guest-info"}' 命令查看libvirt支持命令，打印信息並沒有 guest-network-get-interfaces 命令。原因爲;在虛擬機，裏邊沒有安裝 qga 即 qemu-ga-x86_64.msi -
錯誤二：
libvirt: QEMU Driver error : argument unsupported: QEMU guest agent is not configured解決方法：
錯誤原因：在對應xml文件中，沒有增加對應的接口通道 unix 接口 傳輸信息。接口如下：<channel type='unix'> <target type='virtio' name='org.qemu.guest_agent.0'/> <address type='virtio-serial' controller='0' bus='0' port='2'/> </channel>
思考
其實兩個方案本質上都是調用libvirt底層API。只不過命令方式，只是自己封了一層調用命令。