Practical Experience And Precautions In Building A Hybrid Cloud Architecture Using Us Cn2 Cloud

1.

overall planning and preparation

before formal deployment, complete the requirements analysis (business traffic, delay requirements, scale, backup/disaster recovery strategy). preparation list: public ip, asn (if bgp is required), local firewall policy, identity authentication method (ad/ldap), data synchronization window and rpo/rto. it is recommended to draw a network topology diagram and label the vpc, subnet, vpn/dedicated line, load balancer and storage location.

2.

create a vpc and subnet on the us cn2 cloud

log in to the cloud console or use the api/cli to create a new vpc, plan the cidr (such as 10.10.0.0/16), and then divide the subnets (public subnet 10.10.1.0/24, private subnet 10.10.2.0/24). assign a nat gateway or route to an internet gateway for the public subnet. be sure to avoid cidr conflicts with the local network. if there is a conflict, nat or remapping is required.

3.

security group and network acl design

establish a security group with minimum permissions: the management class (ssh/3389) only allows specified source ip; the application layer port only opens necessary ports (such as 80/443, database port intranet access). enable network acl for additional restrictions, specify inbound/outbound rules and logging policies, and cooperate with the flow logs provided by the cloud for auditing.

4.

select the connection method: ipsec vpn or dedicated line (bgp)

choose according to bandwidth and delay requirements: ipsec vpn for small traffic/temporary use, dedicated line + bgp for large bandwidth/stable low latency. ipsec example (strongswan) configuration points: configure left=local public network ip, right=cloud gateway, leftsubnet=local intranet, rightsubnet=cloud vpc, pfs=yes in ipsec.conf; place the pre-shared key in ipsec.secrets. for bgp, prepare local asn and peer with the cloud, enable md5 password and check mtu.

5.

ipsec vpn configuration example (strongswan)

example snippet - /etc/ipsec.conf: conn cn2vpn { keyexchange=ikev2 authby=psk left=%defaultroute leftid=your public ip leftsubnet=192.168.1.0/24 right=cloud gateway rightsubnet=10.10.0.0/16 ike=aes256-sha1-modp1024 esp=aes256-sha1; } then systemctl restart strongswan, check ipsec status and sudo ipsec up cn2vpn.

6.

bgp dedicated line configuration key points

during dedicated line peering, confirm the asn, bgp neighbor ip, subnet announcement policy and route filtering of both parties. configuration example (quagga/frr): router bgp 65001; neighbor xxxx remote-as 65000; network 10.10.0.0/16. enable route-map for inbound and outbound route filtering, limit announcements to only necessary prefixes and set reasonable local-preference.

7.

internal routing, nat and subnet communication

set the routing table in the cloud: the private subnet to the local area points to the virtual gateway through vpn/dedicated line; the public subnet points to the internet gateway. for private instances that require external access, set up a nat gateway or use snat rules. if necessary, add a static route on the border router: ip route add 10.10.0.0/16 via {{vpn_local}}.

8.

dns and name resolution design

it is recommended to use hierarchical resolution for hybrid cloud: use company ad dns or internal route53 style service internally, and peer-to-peer resolution to private dns (conditional forwarding) in the cloud. configure /etc/resolv.conf on linux to point to the intranet dns, or use dnsmasq for unified forwarding. verify dig +trace and nslookup to ensure that the internal domain name can be resolved on both sides.

9.

data synchronization and storage strategy

determine the master-slave relationship and synchronization tools: use rsync + cron or lsyncd for files; use official replication (mysql master-slave/gtid, postgres streaming replication) or use the database service provided by the cloud for the database. example rsync command: rsync -azp --delete /data/ user@10.10.2.10:/data/. for large-capacity initial synchronization, physical copy or offline transmission is preferred to reduce network traffic.

10.

application deployment and load balancing

deploy application instances in the cloud in a private subnet and provide external services through the cloud load balancer (bind health check). configure health check paths, timeouts and thresholds. for session stickiness requirements, you can use cookies or session sharing (redis/database) at the application layer. test concurrency and connection exhaustion scenarios and adjust connection pool parameters.

11.

monitoring, logging and alerting practices

unified collection of cloud and local indicators and logs: prometheus + grafana collects host/application indicators, and filebeat/logstash or cloud log service receives system and application logs. set key alarms (link interruption, packet loss, abnormal delay, disk/cpu threshold), and establish an alarm receiving strategy (work order/sms/dingtalk/pagerduty).

12.

security reinforcement and compliance attention

enables two-factor, key management (kms), encrypted transport (tls 1.2/1.3), disk encryption. enable traffic mirroring for vpn/dedicated lines for ids/ips inspection. conduct regular security scans (vulnerabilities/ports/weak passwords) and incorporate patch management processes into ci/cd. implement classification and access auditing of sensitive data.

13.

testing and troubleshooting checklist

after completing the deployment, perform acceptance: connectivity test (ping, traceroute, mtr), throughput test (iperf3), delay and packet loss observation, application end-to-end functional test. if you encounter connectivity problems, check the routing table, security group, acl, vpn status (ipsec status/bgp summary) in sequence, and use packet capture (tcpdump) to locate the problem.

14.

operation and maintenance and capacity planning suggestions

regularly practice failover (switching to backup line/local), review whether bandwidth and delay can meet business growth, adjust bandwidth or open more lines on a monthly or event basis. establish a change management process, and any routing/security/acl changes are first verified and filed in the test environment.

15.

cost control and optimization strategies

evaluate cross-region traffic costs and dedicated line costs, prioritize cold data in lower-cost object storage, and use snapshots and lifecycle strategies. use elastic scaling for peak traffic to avoid overprovisioning resources for a long time. regularly audit unused eips, disks, and snapshots, and recycle idle resources.

16.

q&a 1: why choose the us cn2 line to build a hybrid cloud?

q: why is cn2 preferred over ordinary international links? answer: cn2 usually has more stable backbone forwarding, lower packet loss and delay fluctuation, and is suitable for businesses that require real-time and stability (voice, financial transactions). however, cost and dedicated line availability need to be evaluated.

17.

q&a 2: how to ensure the consistency of local and cloud data?

q: how can different storage types achieve controllable rpo/rto? answer: use official synchronization (master-slave/synchronous replication) for the database and make regular full backups; use rsync incremental or cdc tools for files. you can configure the synchronization confirmation process for key data and monitor the delay and loss rate.

18.

q&a 3: what points should be checked first when encountering high packet loss or delay?

q: how to quickly locate when the link is unstable? answer: prioritize checking the physical link and dedicated line status, vpn tunnel renegotiation logs, routing loops or changes, use mtr to locate the hop where the packet loss occurs, and then combine cloud flow logs and local packet capture to locate the root cause of the problem.