I had the same problem. I stopped firewalld, and solved it.
in LVS MASTER, I use tcpdump and found that the LVS do not forward the F packet to RS, and client send F package to LVS again and again
add -e to tcpdump to see the MAC of machine:
tcpdump -i eth0 -nn -e host CLIENT_IP and port 80
10.220.16.105 is the client ip, and
10.220.15.10 is VIP
[root@lvs-1 ~]# tcpdump -i eth0 -nn -e host 10.220.16.105 and port 80
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes
20:54:31.100494 fe:fc:fe:bf:47:9b > fe:fc:fe:ec:9f:61, ethertype IPv4 (0x0800), length 74: 10.220.16.105.50290 > 10.220.15.10.80: Flags [S], seq 2199151220, win 29200, options [mss 1460,nop,nop,TS val 3042809285 ecr 0,nop,wscale 7], length 0
20:54:31.100583 fe:fc:fe:ec:9f:61 > fe:fc:fe:e2:15:d6, ethertype IPv4 (0x0800), length 74: 10.220.16.105.50290 > 10.220.15.10.80: Flags [S], seq 2199151220, win 29200, options [mss 1460,nop,nop,TS val 3042809285 ecr 0,nop,wscale 7], length 0
20:54:31.101908 fe:fc:fe:bf:47:9b > fe:fc:fe:ec:9f:61, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [.], ack 3272581466, win 229, options [nop,nop,TS val 3042809285 ecr 101900523], length 0
20:54:31.101940 fe:fc:fe:ec:9f:61 > fe:fc:fe:e2:15:d6, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [.], ack 1, win 229, options [nop,nop,TS val 3042809285 ecr 101900523], length 0
20:54:31.104153 fe:fc:fe:bf:47:9b > fe:fc:fe:ec:9f:61, ethertype IPv4 (0x0800), length 142: 10.220.16.105.50290 > 10.220.15.10.80: Flags [P.], seq 0:76, ack 1, win 229, options [nop,nop,TS val 3042809288 ecr 101900523], length 76: HTTP: GET / HTTP/1.1
20:54:31.104183 fe:fc:fe:ec:9f:61 > fe:fc:fe:e2:15:d6, ethertype IPv4 (0x0800), length 142: 10.220.16.105.50290 > 10.220.15.10.80: Flags [P.], seq 0:76, ack 1, win 229, options [nop,nop,TS val 3042809288 ecr 101900523], length 76: HTTP: GET / HTTP/1.1
20:54:31.104935 fe:fc:fe:bf:47:9b > fe:fc:fe:ec:9f:61, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [.], ack 263, win 237, options [nop,nop,TS val 3042809289 ecr 101900527], length 0
20:54:31.104960 fe:fc:fe:ec:9f:61 > fe:fc:fe:e2:15:d6, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [.], ack 263, win 237, options [nop,nop,TS val 3042809289 ecr 101900527], length 0
20:54:31.105523 fe:fc:fe:bf:47:9b > fe:fc:fe:ec:9f:61, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [.], ack 280, win 237, options [nop,nop,TS val 3042809290 ecr 101900527], length 0
20:54:31.105547 fe:fc:fe:ec:9f:61 > fe:fc:fe:e2:15:d6, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [.], ack 280, win 237, options [nop,nop,TS val 3042809290 ecr 101900527], length 0
20:54:31.106257 fe:fc:fe:bf:47:9b > fe:fc:fe:ec:9f:61, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [F.], seq 76, ack 280, win 237, options [nop,nop,TS val 3042809290 ecr 101900527], length 0
20:54:31.306408 fe:fc:fe:bf:47:9b > fe:fc:fe:ec:9f:61, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [F.], seq 76, ack 280, win 237, options [nop,nop,TS val 3042809491 ecr 101900527], length 0
20:54:31.711239 fe:fc:fe:bf:47:9b > fe:fc:fe:ec:9f:61, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [F.], seq 76, ack 280, win 237, options [nop,nop,TS val 3042809895 ecr 101900527], length 0
20:54:32.515396 fe:fc:fe:bf:47:9b > fe:fc:fe:ec:9f:61, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [F.], seq 76, ack 280, win 237, options [nop,nop,TS val 3042810700 ecr 101900527], length 0
20:54:34.130929 fe:fc:fe:bf:47:9b > fe:fc:fe:ec:9f:61, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [F.], seq 76, ack 280, win 237, options [nop,nop,TS val 3042812312 ecr 101900527], length 0
20:54:37.352335 fe:fc:fe:bf:47:9b > fe:fc:fe:ec:9f:61, ethertype IPv4 (0x0800), length 66: 10.220.16.105.50290 > 10.220.15.10.80: Flags [F.], seq 76, ack 280, win 237, options [nop,nop,TS val 3042815536 ecr 101900527], length 0
finally, i try systemctl stop firewalld.