mysql+keepalived+orchestrator 构建高可用mysql
作者：互联网
一、需求源：
仅作为实施方收到需求而搭建，不参与应用业务架构讨论。也仅作为构建测试的一点点记录。
1.MySQL 3台server 1主1从1备，keepalived保持vip在主库节点，在主节点和从节点均启动keepalived，3台机器均部署orchestrator。定义 mysqlA 为主，mysqlB为从，mysqlC为备。
2.MySQL节点故障：主节点失效，orchestrator自动切换新的主节点，保持高可用。
3.keepalived 监测本机是否为主节点，如果为主则获取vip。
4.失效节点恢复后作为从节点加入集群。（无要求自动加入，但为满足相对自动化，已写脚本通过keepalived检查并加入。）
二、部署过程：
node OS: centos7.8
mysql version: 5.7.31
keepalived version: 2.1.5
node A : mysqlA 192.168.127.142
node B: mysqlB 192.168.127.143
node C: mysqlC 192.168.127.124
VIP : 192.168.127.150
disable firewalld
setenforce 0
3台机器配置添加hosts
echo '192.168.127.142 mysqlA' >> /etc/hosts echo '192.168.127.143 mysqlB' >> /etc/hosts echo '192.168.127.144 mysqlC' >> /etc/hosts
3台机器互免密登录。
ssh-keygen #一直回车 ssh-copy-id mysqlA ssh-copy-id mysqlB ssh-copy-id mysqlC
因配置了Raft，有多个Orchestrator配置高可用，orchestrator-client会自动选择leader。
3台机器执行 vi /etc/profile，最后添加
export ORCHESTRATOR_API="mysqlA:3000/api mysqlB:3000/api mysqlC:3000/api"
软件列表，各node均需要
[root@mysqlA ~]# ll -rw-r--r--. 1 root root 1081559 Nov 25 06:14 keepalived-2.1.5.tar.gz -rw-r--r--. 1 root root 9116 Nov 25 06:14 mysql57-community-release-el7-8.noarch.rpm -rw-r--r--. 1 root root 10467081 Nov 25 06:14 orchestrator-3.2.3-1.x86_64.rpm -rw-r--r--. 1 root root 10043463 Nov 25 06:14 orchestrator-cli-3.2.3-1.x86_64.rpm -rw-r--r--. 1 root root 15153 Nov 25 06:14 orchestrator-client-3.2.3-1.x86_64.rpm
2.1 keepalived
解压并安装
[root@mysqlA ~]# tar -zxf keepalived-2.1.5.tar.gz [root@mysqlA ~]# cd keepalived-2.1.5 [root@mysqlA keepalived-2.1.5]# ./configure && make && make install
安装keepalive遇到错误1：
configure: error: !!! OpenSSL is not properly installed on your system. !!! !!! Can not include OpenSSL headers files. !!!
解决错误1：
[root@mysqlA keepalived-2.1.5]# yum -y install openssl-devel
编制keepalive.conf
[root@mysqlA ~]# mkdir /etc/keepalived [root@mysqlA ~]# cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/ [root@mysqlA ~]# vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
# notification_email {
# acassen@firewall.loc
# failover@firewall.loc
# sysadmin@firewall.loc
# }
# notification_email_from Alexandre.Cassen@firewall.loc
# smtp_server 192.168.200.1
# smtp_connect_timeout 30
# router_id LVS_DEVEL
# vrrp_skip_check_adv_addr
# vrrp_strict
# vrrp_garp_interval 0
# vrrp_gna_interval 0
#执行脚本的用户，默认是keepalived_script，无则创建，此处用root执行
script_user root
#开启安全脚本
enable_script_security
}
#开启check_run，脚本是检测mysql集群中，谁是master，谁就占用vip。
#interval 脚本执行间隔时间
vrrp_script check_run
{
script "/usr/local/orchestrator/mysqlA_check_master_vip.sh"
interval 2
}
#state 为BACKUP，2台mysql一致；
#interface：名称为网卡名称
#virtual_route_id：2台mysql一致；
#priority：2台mysql一致
#track_script：对应上面vrrp_script的值
#notify_backup：当前keepalived状态为backup时，即不占用VIP时，通过脚本检查mysql状态，并自动以 从 身份加入到集群里
vrrp_instance mysql {
state BACKUP
interface ens33
virtual_router_id 51
priority 80
nopreempt
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.127.150/24
}
track_script {
check_run
}
notify_backup /usr/local/orchestrator/join_MysqlCluster.sh
}
View Code keepalived.conf
mysqlB 配置文件相同，注意修改vrrp_script check_run 中的脚本名字，改为：mysqlB_check_master_vip.sh 。
将keepalived添加到系统服务，AB机均执行。
[root@mysqlA keepalived-2.1.5]# pwd /root/keepalived-2.1.5 [root@mysqlA keepalived-2.1.5]# cp keepalived/etc/sysconfig/keepalived /etc/sysconfig/ [root@mysqlA init.d]# pwd /root/keepalived-2.1.5/keepalived/etc/init.d [root@mysqlA init.d]# cp keepalived /etc/init.d/
至此，keepalived暂告一段落。
2.2mysql
使用yum安装。3台机器均执行。仅做主从复制配置，详细优化参数未设置，要阅读官方天书补充。
rpm -Uvh mysql57-community-release-el7-8.noarch.rpm
#对应的yum安装mysql版本在http://repo.mysql.com查询，el为centos及rhel yum clean all && yum makecache
yum install gcc gcc-c++ openssl-devel mysql mysql-server mysql-devel -y
[root@mysqlA ~]# mkdir /data/sqlite -p
[root@mysqlA ~]# chown -R mysql:mysql /data/sqlite
mysql安装登录密码，查询：
[root@mysqlA ~]# systemctl start mysqld grep 'temporary password' /var/log/mysqld.log
登录mysql后，修改密码：
mysql> SET PASSWORD = PASSWORD('P@ssw0rd');
创建用户，并授权
mysql> CREATE USER 'orchestrator'@'%' IDENTIFIED BY 'P@ssw0rd'; mysql> grant SUPER,REPLICATION CLIENT,replication slave on *.* to 'orchestrator'@'192.168.127.%' identified by 'P@ssw0rd'; mysql> flush privileges;
退出mysql，编制mysql配置文件
[root@mysqlA ~]# cat /etc/my.cnf
[mysqld] symbolic-links=0 log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid #server-id 每台机器不一致，现在以IP后位设定 server-id = 142 log-bin=master-bin binlog_format=row binlog-ignore-db = mysql,information_schema,performance_schema #report_host 为主机名 report_host = mysqlA #开启GTID gtid-mode=ON enforce-gtid-consistency=ON #mysqlC的log-slave-update不配置。 log-slave-updates=1 skip_slave_start=1View Code my.cnf
#在A及B机必须开启的参数
log_slave_updates=1
所有主机重启mysql服务
[root@mysqlA ~]# systemctl start mysqld
所有主机各自添加mysql_config_editor，登录mysql时不用输入密码
mysql_config_editor set --login-path=local --user=root --port=3306 --password
#查看本机mysql_config_editor，注意local对应之前设置的--login-path
#my_print_defaults -s local
#重置所有
#mysql_config_editor reset
#测试
#mysql --login-path=local
设置主从复制，初定架构为：A--->B--->C
mysqlB：
[root@mysqlB ~]# mysql --login-path=local mysql> change master to master_host='mysqlA',master_port=3306,master_user='orchestrator',master_password='P@ssw0rd',master_auto_position=1; mysql> start slave; mysql> show slave status\G
关注如图两项
mysqlC：
[root@mysqlC ~]# mysql --login-path=local mysql> change master to master_host='mysqlB',master_port=3306,master_user='orchestrator',master_password='P@ssw0rd',master_auto_position=1; mysql> start slave; mysql> show slave status\G
查看下面两项值均为Yes，即表示设置从服务器成功。
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
没正式使用之前，验证可同步后，先停掉所有mysql的复制关系。等orchestrator和keepalived正式配置完整后，在启用复制。生产环境慎用 reset master;。
stop slave; reset slave all; reset master;
至此，MySQL暂告一段落。
2.3orcheatrator
3台机器均安装。
下载https://github.com/openark/orchestrator/releases
使用yum安装rpm包
[root@mysqlA ~]# yum install epel-release [root@mysqlA ~]# yum install orchestrator-3.2.3-1.x86_64.rpm orchestrator-client-3.2.3-1.x86_64.rpm orchestrator-cli-3.2.3-1.x86_64.rpm -y
配置
将/usr/local/orchestrator/orchestrator-sample.conf.json 复制到/etc目录下。
[root@mysqlA ~]# cp /usr/local/orchestrator/orchestrator-sample.conf.json /etc/orchestrator.conf.json
编辑 /etc/orchestrator.conf.json
{
"Debug": true,
"EnableSyslog": false,
"ListenAddress": ":3000",
"MySQLTopologyUser": "orchestrator", *** ###与前面添加的mysql用户对应***
"MySQLTopologyPassword": "P@ssw0rd", *** ###密码对应***
"MySQLTopologyCredentialsConfigFile": "",
"MySQLTopologySSLPrivateKeyFile": "",
"MySQLTopologySSLCertFile": "",
"MySQLTopologySSLCAFile": "",
"MySQLTopologySSLSkipVerify": true,
"MySQLTopologyUseMutualTLS": false,
"BackendDB": "sqlite", *** ###使用sqlite，没有使用mysql库，可改用***
"SQLite3DataFile": "/data/sqlite/orchestrator.db", *** ###sqlite文件绝对路径，有文件夹即可。***
"MySQLConnectTimeoutSeconds": 1,
"DefaultInstancePort": 3306,
"DiscoverByShowSlaveHosts": true,
"InstancePollSeconds": 5,
"DiscoveryIgnoreReplicaHostnameFilters": [
"a_host_i_want_to_ignore[.]example[.]com",
".*[.]ignore_all_hosts_from_this_domain[.]example[.]com",
"a_host_with_extra_port_i_want_to_ignore[.]example[.]com:3307"
],
"UnseenInstanceForgetHours": 240,
"SnapshotTopologiesIntervalHours": 0,
"InstanceBulkOperationsWaitTimeoutSeconds": 10,
"HostnameResolveMethod": "default",
"MySQLHostnameResolveMethod": "@@hostname",
"SkipBinlogServerUnresolveCheck": true,
"ExpiryHostnameResolvesMinutes": 60,
"RejectHostnameResolvePattern": "",
"ReasonableReplicationLagSeconds": 10,
"ProblemIgnoreHostnameFilters": [],
"VerifyReplicationFilters": false,
"ReasonableMaintenanceReplicationLagSeconds": 20,
"CandidateInstanceExpireMinutes": 60,
"AuditLogFile": "",
"AuditToSyslog": false,
"RemoveTextFromHostnameDisplay": ".mydomain.com:3306",
"ReadOnly": false,
"AuthenticationMethod": "basic", *** ###打开web时使用basic方式认证，避免免密打开***
"HTTPAuthUser": "admin", *** ###认证用户***
"HTTPAuthPassword": "P@ssw0rd", *** ###认证密码***
"AuthUserHeader": "",
"PowerAuthUsers": [
"*"
],
"ClusterNameToAlias": {
"127.0.0.1": "test suite"
},
"ReplicationLagQuery": "",
"DetectClusterAliasQuery": "SELECT SUBSTRING_INDEX(@@hostname, '.', 1)",
"DetectClusterDomainQuery": "",
"DetectInstanceAliasQuery": "",
"DetectPromotionRuleQuery": "",
"DataCenterPattern": "[.]([^.]+)[.][^.]+[.]mydomain[.]com",
"PhysicalEnvironmentPattern": "[.]([^.]+[.][^.]+)[.]mydomain[.]com",
"PromotionIgnoreHostnameFilters": [],
"DetectSemiSyncEnforcedQuery": "",
"ServeAgentsHttp": false,
"AgentsServerPort": ":3001",
"AgentsUseSSL": false,
"AgentsUseMutualTLS": false,
"AgentSSLSkipVerify": false,
"AgentSSLPrivateKeyFile": "",
"AgentSSLCertFile": "",
"AgentSSLCAFile": "",
"AgentSSLValidOUs": [],
"UseSSL": false,
"UseMutualTLS": false,
"SSLSkipVerify": false,
"SSLPrivateKeyFile": "",
"SSLCertFile": "",
"SSLCAFile": "",
"SSLValidOUs": [],
"URLPrefix": "",
"StatusEndpoint": "/api/status",
"StatusSimpleHealth": true,
"StatusOUVerify": false,
"AgentPollMinutes": 60,
"UnseenAgentForgetHours": 6,
"StaleSeedFailMinutes": 60,
"SeedAcceptableBytesDiff": 8192,
"PseudoGTIDPattern": "",
"PseudoGTIDPatternIsFixedSubstring": false,
"PseudoGTIDMonotonicHint": "asc:",
"DetectPseudoGTIDQuery": "",
"BinlogEventsChunkSize": 10000,
"SkipBinlogEventsContaining": [],
"ReduceReplicationAnalysisCount": true,
"FailureDetectionPeriodBlockMinutes": 5,
"RecoveryPeriodBlockSeconds": 30,
"RecoveryIgnoreHostnameFilters": [],
"RecoverMasterClusterFilters": [
"*"
],
"RecoverIntermediateMasterClusterFilters": [
"*"
],
"OnFailureDetectionProcesses": [
"echo '`date +'%Y-%m-%d %T'` Detected {failureType} on {failureCluster}. Affected replicas: {countSlaves}' >> /tmp/recovery.log"
],
"PreGracefulTakeoverProcesses": [
"echo '`date +'%Y-%m-%d %T'` Planned takeover about to take place on {failureCluster}. Master will switch to read_only' >> /tmp/recovery.log"
],
"PreFailoverProcesses": [
"echo '`date +'%Y-%m-%d %T'` Will recover from {failureType} on {failureCluster}' >> /tmp/recovery.log"
],
"PostFailoverProcesses": [
"echo '`date +'%Y-%m-%d %T'` (for all types) Recovered from {failureType} on {failureCluster}. Failed: {failedHost}:{failedPort}; Successor: {successorHost}:{successorPort}; failureClusterAlias:{failureClusterAlias}' >> /tmp/recovery.log",
"/usr/local/orchestrator/orch_hook.sh {failureType} {failureClusterAlias} {failedHost} {successorHost} >> /tmp/orch.log" ***###添加脚本，当机器master出现硬件故障，或mysql软件故障，即刻漂移VIP，并切换主***
],
"PostUnsuccessfulFailoverProcesses": [ "echo '`date +'%Y-%m-%d %T'` Unsuccessful Failover ' >> /tmp/recovery.log"],
"PostMasterFailoverProcesses": [
"echo '`date +'%Y-%m-%d %T'` Recovered from {failureType} on {failureCluster}. Failed: {failedHost}:{failedPort}; Promoted: {successorHost}:{successorPort}' >> /tmp/recovery.log"
],
"PostIntermediateMasterFailoverProcesses": [
"echo '`date +'%Y-%m-%d %T'` Recovered from {failureType} on {failureCluster}. Failed: {failedHost}:{failedPort}; Successor: {successorHost}:{successorPort}' >> /tmp/recovery.log"
],
"PostGracefulTakeoverProcesses": [
"echo '`date +'%Y-%m-%d %T'` Planned takeover complete' >> /tmp/recovery.log"
],
"CoMasterRecoveryMustPromoteOtherCoMaster": true,
"DetachLostSlavesAfterMasterFailover": true,
"ApplyMySQLPromotionAfterMasterFailover": true,
"PreventCrossDataCenterMasterFailover": false,
"PreventCro***egionMasterFailover": false,
"MasterFailoverDetachReplicaMasterHost": false,
"MasterFailoverLostInstancesDowntimeMinutes": 0,
"PostponeReplicaRecoveryOnLagMinutes": 0,
"OSCIgnoreHostnameFilters": [],
"GraphiteAddr": "",
"GraphitePath": "",
"GraphiteConvertHostnameDotsToUnderscores": true,
"ConsulAddress": "",
"ConsulAclToken": "",
"PseudoGTIDPattern": "drop view if exists .*?`_pseudo_gtid_hint__",
"PseudoGTIDMonotonicHint": "asc:",
"DetectPseudoGTIDQuery": "select count(*) as pseudo_gtid_exists from meta.pseudo_gtid_status where anchor = 1 and time_generated > now() - interval 2 day",
"RaftEnabled":true, ***###启用高可用***
"RaftDataDir":"/usr/local/orchestrator", *** ###orchestrator目录***
"RaftBind":"192.168.127.142", ***###本机的IP***
"DefaultRaftPort":10008,
"RaftNodes":[ ***###3台机的IP***
"192.168.127.142",
"192.168.127.143",
"192.168.127.144"
]
}
View Code orchestrator.conf
复制到其他机器，注意修改文件的本机IP
[root@mysqlA ~]# scp /etc/orchestrator.conf.json root@mysqlB:/etc
脚本：
路径：/usr/local/orchestrator
mysqlA：orch_hook.sh、mysqlA_check_master_vip.sh、join_MysqlCluster.sh
mysqlB：orch_hook.sh、mysqlB_check_master_vip.sh、join_MysqlCluster.sh
orch_hook.sh用途：用于检查master状态，如master硬件故障或mysql软件故障，即切换VIP至从（orchestrator已经自动切换从为新主）；
mysqlA_check_master_vip.sh用途：检查集群MysqlCluster中，谁是master，谁即占用VIP；虽然和orch_hook.sh用途相似，但是上一个脚本没有检查MysqlCluster集群master的功能，当主恢复故障后，是独立master出现，但不在集群里。
join_MysqlCluster.sh：检查本机是否在集群里。若不在，检查本机mysql状态，状态OK自动以 从 库身份加入MysqlCluster集群，并自动启用复制。
orch_hook.sh，在orchestrator配置文件上调用：
#!/bin/bash
isitdead=$1
cluster=$2
oldmaster=$3
newmaster=$4
logfile="/var/log/orch_hook.log"
# list of clusternames
#clusternames=(rep blea lajos)
if [[ $isitdead == "DeadMaster" ]]; then
ssh $oldmaster "systemctl restart keepalived"
elif [[ $isitdead == "DeadIntermediateMasterWithSingleSlaveFailingToConnect" ]]; then
ssh $oldmaster "systemctl restart keepalived"
elif [[ $isitdead == "DeadIntermediateMaster" ]]; then
ssh $oldmaster "systemctl restart keepalived"
fi
View Code orch_hook.sh
mysqlA_check_master_vip.sh，在keepalived配置文件上调用，先本地执行验证无误：
#!/bin/bash
master_node=`orchestrator-client -b admin:P@ssw0rd -c which-cluster-master -i MysqlCluster |awk -F ":" '{print $1}'`
#echo "The cluster-master is $master_node"
#mysqlB_check_master_vip.sh 的不同参数仅为下列两项，互换即可
local_node=mysqlA
remote_node=mysqlB
#echo $local_node
vipadd=192.168.127.150
if [ $master_node == $local_node ];then
local_ip=`ip a show dev ens33|grep -w inet|awk '{print $2}'|awk -F '/' '{print $1}'`
if [[ "$local_ip" =~ "$vipadd" ]];then
# echo "vip is in master"
exit 0
else
echo "master vip is down, restarting now"
ssh $remote_node "systemctl restart keepalived"
# ssh $remote_node "systemctl start keepalived"
fi
else
local_ip=`ip a show dev ens33|grep -w inet|awk '{print $2}'|awk -F '/' '{print $1}'`
if [[ "$local_ip" =~ "$vipadd" ]];then
# echo "vip is in local,release..."
systemctl restart keepalived
# systemctl start keepalived
else
# echo "vip don't in local,exit..."
exit 0
fi
fi
View Code check_master_vip.sh
join_MysqlCluster.sh：在keepalived配置文件上调用
#!/bin/bash
mein=`orchestrator-client -b admin:P@ssw0rd -c which-cluster-instances -i MysqlCluster |awk -F ":" '{print $1}'`
local_node=`hostname`
if [[ "$mein" =~ "$local_node" ]];then
echo "the node in cluster" >> /data/nodestatus.txt
exit 0
eles
echo "will be check status and " >> /data/nodestatus.txt
fi
CHECK_TIME=3
#mysql is working MYSQL_OK is 1 , mysql down MYSQL_OK is 0
MYSQL_OK=1
#function to check mysql status
function check_mysql_helth (){
mysql --login-path=local -e "show status;" >/dev/null 2>&1
if [ $? = 0 ] ;then
MYSQL_OK=1
else
MYSQL_OK=0
fi
return $MYSQL_OK
}
while [ $CHECK_TIME -ne 0 ]
do
let "CHECK_TIME -= 1"
check_mysql_helth
if [ $MYSQL_OK = 1 ] ; then
CHECK_TIME=0
#mysql status is OK,then try join MysqlCluster
#get MysqlCluster master_node
master_node=`orchestrator-client -b admin:P@ssw0rd -c which-cluster-master -i MysqlCluster |awk -F":" '{print $1}'`
#copy to master_node,set read_only,and start slave;
mysql --login-path=local -e "change master to master_host='$master_node',master_port=3306,master_user='orchestrator',master_password='P@ssw0rd',master_auto_position=1;set global read_only=1;start slave;"
#check slave status, shuoult be check Slave_IO_Running & Slave_SQL_Running
Slave_IO_Run_status=`mysql --login-path=local -e "show slave status\G" |grep Slave_IO_Running |awk -F ":" '{print $2}'`
if [ $Slave_IO_Run_status == Yes ]; then
echo "Slave_IO_Runing is Yes"
else
echo "Slave_IO_Runing is Error"
exit 1
fi
Slave_SQL_Run_status=`mysql --login-path=local -e "show slave status\G" |grep Slave_SQL_Running |awk -F ":" '{print $2}'`
if [ $Slave_SQL_Run_status == Yes ]; then
echo "Slave_SQL_Running is Yes"
else
echo "Slave_SQL_Running is Error"
exit 1
fi
exit 0
fi
if [ $MYSQL_OK -eq 0 ] && [ $CHECK_TIME -eq 0 ]
then
#pkill keepalived
exit 1
fi
sleep 10
done
View Code join_MysqlCluster.sh
3台机器启动 orchestrator服务
[root@mysqlA~]# systemctl start orchestrator [root@mysqlB~]# systemctl start orchestrator [root@mysqC~]# systemctl start orchestrator
登录web界面，由于未启用eepalived，所以用其中1台IP登录，并做发现：
Discover a new instance
输入mysql地址或主机名
发现完毕
刷新，回到集群，重命名集群一个别名
新的集群别名，要和脚本上的变量一致
回到集群
各节点状态及自动生成的复制拓扑。
直接在拓扑图上修改从库的复制关系：
拖动修改主库，官方翻译为优雅的进行主从切换，切换后，旧主为从，需要重新启动slave，手动，暂无写脚本检测并启动。
临时写了一个 优雅切换主从后的 新从 启动复制脚本
在 新从 服务器上 ./orch_hook2.sh
#!/bin/bash
mysql --login-path=local -e "stop slave;"
new_master_node=`orchestrator-client -b admin:P@ssw0rd -c which-cluster-master -i MysqlCluster |awk -F":" '{print $1}'`
mysql --login-path=local -e "change master to master_host='$new_master_node',master_port=3306,master_user='orchestrator',master_password='P@ssw0rd',master_auto_position=1;set global read_only=1;start slave;"
View Code orch_hook2.sh
结语
##测试过程排错让人迷失方向---必须读懂官方文档---感谢搜到的国内几篇好文##
参考资料：
https://github.com/openark/orchestrator
https://www.cnblogs.com/zhoujinyi/p/10394389.html
https://zhuanlan.zhihu.com/p/139294374
1、我在构建MySQL的时候，确实是门外汉，太多配置参数、优化参数都不知道是什么，有什么用。像GTID，不启用的话，主从切换复制每次要show master status，记录File、和Position。测试过程还遇到 数据库复制正常，但不同步、reset master后的恢复、导出导入恢复...一言难尽。
2、keepalived 回首一看，也有5-6年没碰过这玩意了，配置文件很多参数都不知道怎么用了。调用脚本那里栽了几个跟斗。
3、orchestrator，今年首次认识这个东西，然后一直思考这个东西有什么用，能自动切换，能恢复拓扑，能。。。还以为主库挂了之后能自动恢复，结果只是我以为。
4、脚本也是写的太烂了，本来脚本能力就差...
标签：orchestrator,keepalived,mysqlA,master,mysql,root 来源： https://www.cnblogs.com/leeby/p/14054593.html