整理一下：
1.建议免费期后再开通，免费期内开通免费期到期后会删机。
2.处理器： 总共4个OCPU，内存： 总共24 GB，再往大调可能面临收费。
3.建议使用ubuntu系统时，不要选minimal。
4.目前美西圣何塞无法使用，具体原因未知。
5.具体的免费内容文档里有清楚的标明https://docs.oracle.com/en-us/iaas/Content/FreeTier/freetier_topic-Always_Free_Resources.htm#resources
其他注意事项欢迎吊大的继续补充。
BY wulabing的杂谈blog
Some messages aren’t supposed to last forever. There are some Telegram groups and conversations where it’s best if messages are automatically deleted in a day or a week. Here’s how to auto-delete messages in any Telegram chat. You can enable the auto-delete feature on a per-chat basis. It works for both one-on-one conversations and group chats. Previously, you needed to use the Secret Chat feature to automatically delete messages after a set time. At the time of writing, you can choose to automatically delete messages after a day or a week. Telegram starts the timer once they are sent, not after they are read. This won’t affect the messages that were sent before enabling the feature.
Launched in 2013, Telegram allows users to broadcast messages to a following via “channels”, or create public and private groups that are simple for others to access. Users can also send and receive large data files, including text and zip files, directly via the app.The platform said it has more than 500m active users, and topped 1bn downloads in August, according to data from SensorTower.wulabing的杂谈blog from tw