The manager shall be the chief administrative officer of the city. He shall be chosen by the council solely on the basis of his training, experience, and administrative qualifications and need not be a resident of the city at the time of his appointment. The city manager shall be appointed for an indefinite period and may be removed by the council at any time; but after he has served as manager for one year, he may demand written charges and a public hearing on the charges before the council prior to the date when his final removal takes effect. After such hearing, if one is demanded, the council shall have unlimited discretion either to reinstate the manager or make his removal final. Pending such hearing and removal, the council may suspend the manager from office. The council may designate some properly qualified person to perform the duties of the manager during his absence or disability or while the office of manager is vacant.